Sometimes our MacBooks, MacBook Pros, or Macs don’t recognize our external drives or external thumb drives. This situation often occurs after you initially eject the external drive and unplug it from your computer. When you try to plug in the drive again, your Mac no longer sees it. It won’t mount at all and acts as if it’s utterly invisible to macOS.
In many cases, the only way to solve this problem is to completely remove the external drives and then restart your MacBook or Mac several times until the drives finally show up again.
There are several reasons why your Mac won’t recognize a drive. If you have a disk already mounted and your system goes to sleep, it also powers down ports, including USB ports. When you wake your Mac up, for whatever reason, your external drive does not wake up.
Quick Tips
Follow these quick tips and get your Mac to recognize and mount your external drives
If using a hub, try using a different port on your Mac for the hub or plugging your external drives directly into the Mac
Check your USB connections for a snug fit or frayed cables, missing pins
Connect the USB device to its own power source, if possible
Update Finder Preferences to show external drives
Perform an SMC & NVRAM reset
Run Disk Utility to Mount, Verify, or Repair Drives
Use Terminal Commands diskutil list, diskutil info disk, & diskutil eject disk
It’s easy to plug things in at random times, and usually, our Macs and MacBooks get it right and recognize everything. That’s why most USB devices are called plug-and-play. But this doesn’t always hold true. So it’s better to follow the recommended path to connect your external device(s) to your Mac.
The best (or least problematic) method for connecting external drives
Turn ON your Mac or MacBook
Plug in the USB cable into the Mac and to the device
Do not use a hub–plug your drive directly into your Mac’s port
THEN Turn ON the external drive when the USB cable is connected
Using a hub? Think again
A lot of readers discovered that their older model hubs no longer worked in macOS. So check if the hub is the problem by plugging the external drive directly into the Mac.
If the drive is now recognized, the problem is likely the hub. First, try plugging the hub into a different port on your Mac.
Strange but true, some users found that their thumb drives work when they plug it in exceptionally slowly.
When they try and plug in the USB flash drive normally, their PC’s don’t recognize the disks.
But if they gently slide them into the port in slo-mo, their drives are recognized! Go figure.
The same trick works for all types of computers, Windows or Macs, Desktops or Laptops!
Power Problems
This error frequently occurs when the hard disk is not receiving enough power from the port. If you instead plug the drive directly into a power source (if a power supply is available for your drive,) the external drive usually mounts on its own now that it has sufficient and steady power.
If your drive doesn’t allow for an external power source, try connecting the drive to another USB port. Or plug it into a self-powered USB hub.
Often, our MacBooks don’t put out enough power across the built-in USB hubs and so adding a self-powered hub sometimes solves the problem straight away.
If your MacBook is not mounting an external hard drive or flash drive, try plugging in the power cable to the MacBook and reconnecting the drive. This tip often does the trick!
Rejecting the Ejecting
Another common reason is when you remove the drive without first ejecting. Instead of just pulling out drive connections, always perform a safe remove when ejecting external devices.
Options include right-clicking on the icon of your external drive and selecting “Eject device.”
Or just drag the drive icon to the Trash, changing it to an Eject symbol.
The rule of thumb for external drives is always to shut down, eject, or otherwise disable before unplugging.
This process means that the software “turns” it off before the hardware.
A Tight Fit is a Good Fit
Another reason for your Mac not recognizing external drives is a dirty or loose connection between your cable, USB-C multi-adapter, Thunderbolt 3, or other connecting ports.
So check your cable, your dongle (if used), any additional adapters, and the ports on both computers and drive to ensure that they are clear, clean, snug and fit tightly to each other.
Check that the cable connecting to the ports is indeed connected. Loose connections often lead to external drives not being recognized. Or even if they are recognized, they randomly disconnect without warning or prompting. A similar issue is frayed or worn cables, so make sure that your cable is in good condition.
If you use a hub for your connections, if possible try to connect your external drives directly into your Mac–no intermediary.
Check Your Settings
Sometimes it’s the simple things that trip us up. So before performing any complex troubleshooting, let’s look at some settings.
Go to Finder > Preferences.
Under both the General and the Sidebar tabs, see the section “Show these items on the desktop: (or sidebar:)”
Now verify that External Disks and Hard Drives have a checkmark in the box. If not, click it to enable your external drive icons to show on your desktop.
External hard drive won’t mount in macOS High Sierra or above?
When you are in Disk Utility, look in the upper-left corner and find the View option. Click on View, and you should get an option to Show All Devices.
Reset NVRAM
How to reset NVRAM
Shut down or restart your Mac, turn it on and immediately hold down these four keys together: Option, Command, P, and R. Keep pressing these keys for a minimum of 20 seconds. It might look like your Mac restarts.
And if your Mac plays a startup chime when you turn it on, release the keys after hearing a second startup sound.
Also, you might reset the System Management Controller (SMC.) See these steps under the section “Does Your MacBook Shut Down When You Plug In Your External Hard Drive?”
Run Disk Utility
Open Disk Utility and see if your external drive appears here. Find Disk Utility in Applications > Utilities > Disk Utility. If your drive shows up but is not mounted, select the mount option which should mount that disk.
To verify, click on the Apple logo in your screen’s top left corner and select About This Mac. Select the Storage tab and see if your drive appears here.
If not, return to Disk Utility and select your external drive from the left sidebar.
Now choose First Aid or verify (repair) disk. This process should find and correct any minor errors with your drive.
Check Disk Format
If you can see your drive in Disk Utility but were not able to mount and use it, you might have a disk format problem.
Look and see if your external drive is listed as NTFS format, if so you want to reformat the drive using the erase function in Disk Utility and format it as exFAT, FAT, APFS (if supported) or Mac OS Extended.
Look at Your System Information
Let’s go to System Information and see all the USB devices connected to your Mac. Navigate to the Apple in the upper menu > About this Mac > Storage
For more details, go to the Apple Menu> About this Mac > and select System Report below the information about your Mac and its OS.
Terminal to the Rescue!
If System Information recognizes your USB external drives, but they continue not to show up, try disconnecting them and then remount the drives via Terminal.
Find Terminal in Applications > Utilities > Terminal.
Once open, type in the command diskutil list
The diskutil list command displays basic information about all available volumes and drives attached. So it’s a good command to use when checking if drives are really connecting to your computer.
Once you type in the command, you see a list of all your disks.
Look for the section labeled /dev/disk_ (external, physical).
The disk_ part is the physical disk identifier, and the underscore is whatever number or digit is assigned to this drive–make a note of that whole line including the numbers or digits following the word disk.
For partitioned drives, an “s” follows the disk identifier. The number following the letter “s” represents the partition number.
So, if a disk has two or more partitions, the total disk identifier looks something like this:
disk3s1
disk3s2
disk3s3
Now, put in another command into Terminal diskutil info disk_. Make sure to add the number or digit assigned to this drive at the end, in place of the underscore.
For example, my external thumb drive is listed as /dev/disk4 (external, physical) so I type in the command diskutil info disk4. This command opens up detailed information about the drive, including its manufacturer name, the size, if it’s removable and further facts.
Once you establish that the drive is known by your system, use Terminal to eject that disk through the command diskutil eject disk _.
Remember to use the disk identifier number that associated with your drive in place of the underscore. Once you execute that command, type in diskutil list again to see if your disk is now gone from that list.
Once the drive is gone, physically remove it from your computer and then reinsert it — hopefully, your drive mounts and works as usual.
Terminal commands not working or seeing “operation not permitted” in macOS Mojave and above?
If your Mac is not allowing you to enter and execute Terminal commands, you need to grant the Terminal app full disk access.
Please see this article for details on how to grant the Terminal app access to your full disk.
Does Your MacBook Shut Down When You Plug In Your External Hard Drive?
This happens when your hard drive draws too much power or an ‘incorrect’ amount of power from the USB. Your Mac’s SMC shutdowns the computer to protect itself.
If this happens frequently, connect the drive to its own power source if possible, so it’s not siphoning power from the USB port.
If that’s not feasible (like thumb drives), try a different USB port or if applicable, a different USB cable. Also, reset your Mac’s SMC.
Resetting SMC
If the battery is nonremovable
Shut down and unplug the power adapter
Press Shift-Control-Option on the left side of the keyboard AND press the power button at the same time. Hold these keys and the power button for 10 seconds
If you have a MacBook Pro with Touch ID, the Touch ID button is also the power button
Release all keys and reconnect your Mac to the power adapter (plug it into an outlet)
Press the power button again to turn on your Mac
If the battery is removable
Shut down your Mac and disconnect the power adapter
Remove the battery
Press and hold the power button for 5 seconds
Return the battery and reconnect your Mac to the power adapter (plug it into an outlet)
Push the power button to turn on your Mac
Inspect with Console
For most of us, Apple’s Console app is a confusing list of logging messages and errors that make sense to an everyday user. But in times of trouble, Console is really quite useful, especially when you can’t figure out what the heck is going on!
In a nutshell, Console displays log information that helps you or a service provider troubleshoot problems on your Mac. Console won’t fix the problem, but it does provide information to diagnose the problem.
It’s never been easy to work with Console, but the good news is that starting with macOS Sierra, Apple retooled Console to make it a bit more user-friendly or at least DYI technician friendly.
So, let’s use Console to check that your USB port is detecting your devices. Find Console in Applications > Utilities > Console.
The console utility lets you know if your external USB devices are detected and if there are any errors. Before you attach your USB drive, open Console and select the Error and Faults Tab, now plug in the drive and look to see if it detects your device or if there’s an error.
If Console shows that nothing happened and no errors pop up, then your problem is not the USB device.
External Drives Very Slow after macOS Update?
Many readers have recently reported that they are experiencing slow down issues with their external drives after updating to macOS Catalina or Mojave.
If you are experiencing issues with your external drives after updating to macOS Mojave, your best bet is to reset the SMC and then try connecting to the external drive.
Reset SMC on MacBook
To do the SMC reset, start with Shutting down the Mac.
Press Shift-Control-Option on the left side of the keyboard, then press the power button at the same time.
Hold these keys and the power button for 10 seconds.
After the 10 seconds, release all keys. Then press the power button to turn the Mac on.
Resetting SMC on Mac Mini
If you are using a Mac Mini, simply shut down the Mac.
After your Mac shuts down, unplug the power cord.
Wait 15 seconds then plug the power cord back in.
Wait another 5 seconds, then press the power button again to turn on your Mac.
Now, try to connect the external drive and see if it is more responsive to your Mac.
Let’s Have a Third-Party
A lot of Mac users and lovers recommend using the third-party app Kext Utility to solve their problems recognizing external drives. Readers who could not mount their USB 3.0 and 2.0 FAT and FAT 32 External Drives on their Macs ran the program Kext Utility and after rebooting these USB drives worked!
Kext Utility runs on Mac OS X 10.5 or later. For macOS users, make sure you run the latest version.
Wrap Up
Sadly, Macs not recognizing external drives is nothing new. It’s a perpetual problem, especially after updating your Mac’s operating system to the latest macOS or OS X. But the good news is that quite a few solutions are available to fix this temporary issue (hopefully, it’s just that!)
Reader tips
If you use a hub for multiple external drives, try removing your hub or switching to a different (and newer model) hub. For me, when I used my hub, my drives didn’t show up or work. But when I plugged the disks directly into the iMac via USB, everything worked fine! No matter what I did, the hub would not work. So I purchased and installed a new multi-port hub (self-powered) and everything is working again. As an FYI, this happened after updating to macOS Mojave and even Apple Support could NOT identify the problem or explain why the hub that worked with High Sierra stopped working after the update to Mojave
I need to update my external disk’s driver. So you might want to contact the external drive’s manufacturer support department and see if there is an update for that drive and for the macOS or Mac OS X version you use
Go to System Preferences> Spotlight and deselect everything that shows up in that list. After you untick all the boxes, plug in your external drives. Once your external drive(s) is recognized, go back to System Preferences > Spotlight and set it back to the default spotlight search preferences by ticking all the boxes
Solved the problem by going to Preferences within Disk Utility and checking “Automatically Open Read-Only Images.” It turns out my USB thumb drive was read-only because it’s natively formatted as NTFS. That particular preference was off and prevented the drive from even showing up. Just do a quick reformat (if nothing is on the drive or nothing important), and all is well
If you changed your Mac’s system icons as Trav did, the solution is relatively simple and involves changing icons back to normal
For most of her professional life, Amanda Elizabeth (Liz for short) trained all sorts of folks on how to use media as a tool to tell their own unique stories. She knows a thing or two about teaching others and creating how-to guides!
Her clients include Edutopia, Scribe Video Center, Third Path Institute, Bracket, The Philadelphia Museum of Art, and the Big Picture Alliance.
Elizabeth received her Master of Fine Arts degree in media making from Temple University, where she also taught undergrads as an adjunct faculty member in their department of Film and Media Arts.
I have a mid 2012 MacBook Pro 13 inch. I am trying to connect a USB-C SSD via an apple USB-C to Thunderbolt 2/3 adaptor and an apple thunderbolt 2/3 cable to the thunderbolt port . The SSD is not at all recognised.
It is recognised via the usb 3 port. I would however like to take advantage of the faster speeds of the thunderbolt port?
I have a Acer cheapo laptop running Windows 8…never, ever had a problem recognising drives etc. updates to latest Firefox runs well (Mountain Lion can’t run anything anymore as the Bible says : ‘better to be a live dog then a dead lion’) and fast (ssd only 4GB of ram, i5) My iMac, same age can’t run anything unless it has the right yearly released stupid MacOS ( 9 different ones in as many years compared to Window 2!) I only use Apple rubbish for Logic software. They are badly made, their operating system is cumbersome at best, clumsily designed, not intuitive. I’m trying to upgrade a Mountain Lion OS to El Capitan (who thinks up this silly primary school nonsense?) Won’t see external HD, download this, research that. One week in and still working on it. Artificial Intelligence? Do me a favour we can’t even get passed Artificial stupidity, designed by morons who live a silicon vally bubble. Now, rant over. Apart from that everything is fine and the iMacs still ain’t able to browse the internet. Happy days.
Nowhere is mentioned the strict, by-design incompatibility of MacBook pro circa 2012 that has an internal superdrive (obviously non-functioning so as to need an external) with the Apple External SuperDrive!
And nowhere do you identify other, non-APPLE external optical drives that would work with the beleaguered 2012 MacBook pro.
(I would rather not take the chance of corrupting the terminal and making my computer as non-functional as the internal drive).
Thank you so much for this article! My 2017 MacBook Pro suddenly decided it wouldn’t detect the charging cable – which was a bit of an issue with only 20% battery power left. I thought it was probably a battery issue but then it wouldn’t detect a back-up disc either. Rest the SMC as outlined above and Bob’s your uncle – all working again!
I’m about to give up with my Mac!
Originally I copied complete hard drive, videos, docs, pics, music onto an external no problem.
However since then it has never recognised it at all.
Also I reformatted another external to backup, same thing never recognises it.
Absolutely useless & wasted hours trying to find a solution.
Back to Windows!
I have a MacBook Pro late 2011 using ElCapitan 10.11.6. It has 2 USB 2.0 Ports and I have an Insignia 2.0 -7 port Hub, external power, attached to one built in hub and the other built in hub has a Passport 0748 2TB storage hard drive plugged in.
I have another D-Link 2.0 7 port hub, no external power plugged into one of the 7 Insigna ports.
I have Macintosh HD 1 TB internal drive.
I have 5 USB external drives, A Passport 0748 2 TB hard drive, A Passport 070A 1 TB hard drive, A Passport 2626 2 TB hard drive, a Seagate back up & desk 5 TB external power hard drive and a My Book 1234 2 TB external power hard drive.
Because I need to continue to use a Lion 10.7.5 system, the My Book 1234 is a 2TB Macintosh HD 10.7 bootable disk plugged into one of the D-Link ports and the Macintosh HD has the bootable 10.7.5 System. I needed to have a newer system to use my browsers and other new applications so the bootable ElCapitan system boot disk 10.11.6 is on the Passport 2626 which is plugged into one of the 7 Insigna Ports. That is ElCapitan disk boot system I am presently using. The Passport 070A, 1TB hard drive is plugged into one of the 7 Insigna ports is used for storage and is not bootable. The Seagate 5TB back up & desk is my back disk and is plugged into one of the 7 D-Link ports. Finally, the Passport 0748, My Passport 2 TB disk is a main document storage disk plugged into the 2nd built in USB 2.0 port. This My Passport 2 TB disk is visible on the System Information USB tree but is not visible on the Disk Utility list nor the desktop of the ElCapitan system.
I have plugged the My Passport into every built in port and in to ports on the Insigna 7 port hub and the D-Link 7 port hub. It always shows up on the System Information USB tree, but never shows up on the Disk Utility. I have plugged it in fast…I have plugged it in slow, I have plugged in and re-booted, I have plugged it int to all hub ports after re-booting, I have unplugged it and replugged it in. It never shows up… Ever.
This disk contains all my engineering and surveying documents over a period of 30 years. It was working very well, but I have recently been shutting my computer completely off at and in the morning boot up (off the Passport 2626 ElCapitan disk, sometimes all of the passport disks will not work and the computer defaults and boots up off the internal disk. The external power disks Seagate and My Book 1234, Macintosh HD 10.7 always are visible as is the internal Macintosh HD disk.
Usually the visibility can be overcome by just plugging and unplugging in the disks or plugging them directly into the built in port. If any of the passport disks are plugged to the built in ports when booting up they show up… EXCEPT the Passport 0748 My Passport disk. It only shows up on the System Information tree.
The oldest external disks are….. in order, oldest first… Seagate, My Book, Passport 0748, Passport 070A and Passport 2626 (new). The built in hard drive is the oldest of all.
How do I get this disk to mount so I can use it to transfer information to another new disk?
Sorry to hear about your problems with your Passport drive. It sounds like you exhausted a lot of troubleshooting options.
Have you tried plugging the Passport into another Mac to see if it mounts? If not, I would give that a try to see if it’s the Disk that’s the problem or something on your Mac.
Hi
Recently updated to high sierra on an old mac, (yes I am that behind with updates!), now it won’t let me access a Samsung Hard drive i used to use.
It won’t mount using disk utility.
I can see it using the Terminal and have ejected it like you said, however even though it says ejected, and the light on the hard drive turns off, it is still listed when I type diskutil list. When I plug in again, it still won’t let me access it (nothing appears in finder).
I am having these issues where my hard drive (that has previously connected well) is not showing up!
When I go to disk utilities, the page never loads so I can’t remount it if that is the issue.
I was wondering if I unplug it from my computer without ejecting (since my computer isn’t even reading that it’s plugged in) if it will corrupt my hard drive?
I do not want to lose all the photos I have on it, however I don’t want to just leave the drive plugged in if it is not showing up.
Hi Liz,
I have a MacBook Pro 2016 and a my passport for mac hard drive which stopped mounting. I have done pretty much everything you suggested including terminal- force mounting (does detect before that) – comes up with unknown special file or file system message. In console – not sure how Hard drive specific errors would look like.
It is coming up in disk utility (in grey) but no first aid or mounting is working.
Any other ideas that could work for troubleshooting?
Cheers
Cris
After installing the latest update macOS High Sierra V 10.13.6 my laptop will not eject the disk using Terminal commands. I receive a response that It “timed out”
Command used was diskutil eject disk3
I’m doing this because the external drive only shows in Terminal; when checking drives, it indicates the external hard drive is not mounted; and I’m unable to mount it.
I have a Macbook Pro 17-inch Mid 2010. Everything was working fine until the update was installed.
Why are Macs so terrible?
It feels like a half-finished program. How can they charge three times as much for something that works a tenth as well and then be considered anything other than crap?
I don’t get it. The biggest waste of money ever has been a Mac, spend $4,000 for a computer that does half the stuff in twice the time, and has another problem with each update.
Just junk.
I had to pull out an old Windows PC and do the work on it because it sees the hard drive perfectly.
Congratulations to whoever wrote this, as a person who used to write guides for the use of a govt agency crash system these instructions are excellent , simple , great use of screen shots and written in a friendly not too technical way. 10/10
Hi I have an external hard drive and suddenly my mac stops reading it. There is no icon on the desktop. Disk functions ok with other pcs. When i go to Terminal and type diskutil info it appears there. What can i do to unblock this situation?
Try using Disk Utility (in Applications > Utilities) to mount the disk (you may need to verify it or run first aid) or use Terminal with the command: diskutil mount /dev/diskXXXX (where XXXX is your disk’s number as shown in diskutil list)
I have an issue with my MacBook, yes, it is that old. One day it is running slow, but working. Next day, I get a blinking file folder with a ?. I have been trying to restore, but it is not taking it. Been trying for 3 days. Yes, I am giving up…for now. I had to remove the internal hd to make it an external. It kept running the install disk, Snow Leopard, and it kept doing it no matter if I restored it or not.
Now, I no longer see the hd! I ran discutil but it is no longer finding it. What the hockey sticks happened and how do I fix it?
It shouldn’t be so complicated for a Mac to recognize a USB that was working before.
Spending hours trying to connect something to your computer is bonkers.
The amount of working time I am losing trying to do this is insane.
Moreover, I don’t have access to all my stored information.
I am really fed up with this.
Not even mentioning the supposedly superior Mac for photos that almost burn out every time I try and download the camera pictures to it. My 8-year-old PC worked better than this. Worst upgrade in a computer ever!
Hello,
my imac 6.1 late 2006 does not recognise bootable FlashDrive for installing WIndows 10 with the help of bootcamp. Please advise how should I proceed to achieve the aim.
When the drive is flashing, it usually means your Mac is running through a series of check to mount the drive. And for some reason, it’s getting stuck in this process.
Try using Terminal to eject the disk, then shut down your Mac, wait 20-30 seconds and unplug the external drive from the Mac, and power your Mac back on. Wait for your Mac to fully boot, then reconnect the drive to your Mac and see if it now recognizes it.
1) open Terminal (in Applications > Utilities)
2) type in this command: diskutil list — this shows a list of all internal and external disks
3) locate your external drive in the list and find its identifier listed as: /dev/disk(#) where # is the disk’s number in your system
4) type in these commands to eject your external drive: diskutil unmountDisk /dev/disk# followed by the command: diskutil eject /dev/disk# make sure you replace # with the number of your external disk as listed in your system disk list
After ejecting, shut down, power back up, and connect the drive after fully booted.
I was having the same problem, and tried the diskutil in Terminal. My disk still doesn’t appear here either. Do you have any other suggestions? Thanks in advance for your help!
Hello!
I have an external lexar ssd 512mb that I usually use on my MacBook Pro. Suddenly yesterday when I restarted my laptop the disk stop showing up. I tried disk utility but the lexar is not showing up too. in my laptop I’m using mojave about quite a time. I tried the console and not showing up.
Then I connect the drive to my old iMac with Sierra, and the disk mounts and shows up. Tried to format again, only appears on Sierra and not mojave.
Also appears in windows but not mojave.
Does anyone has a solution?
Thanks.
I recently purchased a 1Tb External SSD hard drive to use on my Macbook Pro and iMac.
When I plug the drive in the computer tells me it is unable to read the disk and I’m presented with the Dialog box asking me if I’d like to initialize or eject the disk.
When I choose Initialize I get the Error “Disk Erase failed with the error: “Unable to write to the last block of the device”.
I read one of your answers to a previous post and used Terminal to inspect the disk.
Sorry about your troubles with your external drive.
Was the drive you purchased for a Mac or Windows or unformatted?
Also, what format are you choosing to initialize the drive with? The current recommendation from Apple is Mac OS Extended (Journaled) not APFS, FAT, or exFAT.
If you purchased it for Mac and it’s not recognizing it, I recommend you return the drive to the place of purchase or contact the manufacturer. That drive (for Mac) should work out of the box with no formatting required. Since it isn’t working, I would be skeptical about long term performance and stability, even if you are successfully able to reformat it.
You could try using a different cable and/or port on your Mac–sometimes we see these types of error when there is a problem communicating.
Another option is to launch into Recovery Mode (Command+R) and open Disk Utilities from there to format the drive. It might work.
All in all, the fact that a new drive is giving you these errors makes me suspicious that it won’t perform well over the long term–so if you can return it or replace it, do so now.
Hi, many thanks for all this great info. Unfortunately, my WD Passport USB external hard drive is being particularly stubborn. I’ve tried your suggestions, bought a new cable and tried other macs but still no luck.
The hard drive powers up normally with no weird noises and has a continue white light (no flashing) and as far as I can see all is normal. But for some reason, it is not showing up in Disk Utility, Terminal or Console.
Thanks for getting back to me. It’s greatly appreciated! Unfortunately, System Report is only showing Apple Internal Keyboard/Trackpad, BRCM20702 Hub and Bluetooth USB Host Controller 🙁 Many thanks for your suggestion!!
You mentioned you tried this on other Macs as well and the drive didn’t show up either–correct? If you have quick access to another Mac, I would try connecting the drive and see if another Mac picks up the drive using System Report or elsewhere.
Also, before connecting the drive to your Mac or any other:
1. Close all apps
2. Shut down the Mac
3. Once powered off, connect the drive and if available, connect the drive to its own power source
4. Power up the Mac
5. Remember to try multiple ports on the Mac–just in case there is a problem with a port
If the problem replicates on another Mac, then the problem is likely some hardware issue in the drive itself–perhaps a loose cable or some other issue. In that case, you can either take the drive itself into a repair shop OR if you like tinkering around DYI, then you can open up the drive’s case and take a look for any obvious problems, like a lose or detached internal cable.
Hello, I read this article, you described so deeply. As you said “There are several reasons why Mac won’t recognize a drive. If disk already mounted and system goes to sleep, it also powers down ports, including USB ports. When you wake your Mac up, for whatever reason, your external drive does not wake up”.
It is right because generally sometimes an external hard drive doesn’t show up on Mac. It is very bad when you need to transfer something right then. It can be risk that on the external drives which means you cannot transfer what you need between devices at all.
I did not know why this happen then I searched and found that it happens because multiple reasons like faulty cable, damage USB port, file system corruption, and so on. But if external drive’s data is not accessible due to file system corruption then it can be cause of data loss.
One more point, I would like to share about data recovery software. During research I found that there are software available online that are very helpful if some lost data during this update, they can recover easily. I read reviews and most of them suggested Stellar Data Recovery. I used free demo to check and found better result.
But, I am wonder to read this blog because of you described a so many tips or solutions to fix it which I did not know. Very useful article for me I personally believe. Thank you so much.
I struggled for over a year with failure-to-mount my Time Machine external disk on MacOS (10.11).
I knew the drive and cable were okay. A reboot would always fix, but who wants to do that every few days?!
I tried all kinds of advice from these sites and forums; wasn’t fsck; resetting SMC had no effect; nothing but a restart seemed to work.
Then when the same problem immediately appeared on a new/second Time-Machine disk of different make, I finally tried a stupid-lame trick of switching USB ports.
“Okay,” it says! I can’t predict which of the two ports will work on any given attempt (still new to the trick and have not nailed down a pattern).
But so far if one port fails, the other works (swapping roles).
Bizarre, and still annoying.
But it’s looking like I won’t have to keep rebooting so often.
It is the first one which talked about what I am sure is my issue, namely power and recognizing external disks with a port expander.
My situation is that I have 3 USB disks connected to my High Sierra based Mac using an Ankar powered port expander.
On my older Mac running macOS Sierra, this was not a problem.
But now with my new Mac Pro connected through the new Thunderbolt connector, not all of the disks mount when I turn the computer on.
Sometimes none, sometimes several.
Unplugging the various disks and reconnecting them eventually gets them all to work, but there is no procedure I have worked out that reliably gets them all to mount.
If anyone who has experienced this problem has found a permanent solution I would be interested, even if I need to buy a different port expander.
I have a Toshiba Canvio external hard drive that works fine on MacBook pro-2015 Yosemite, but when I try to use it on my new MacBook Pro-2018 Mojave it doesn’t recognize.
I see it grayed out in Utilities and I just need to know if I try to mount it there will I lose my files?
I have important files in it and can’t risk losing them.
We suggest you NOT mount it on the MacBook Pro with Mojave since it is not auto-recognizing that drive.
It should see it, but since it isn’t and you mention it has very important files, then leave it.
What we do suggest is purchasing or borrowing an external drive that does work with your new MacBook Pro and then duplicating those important files onto that drive using your older MacBook.
Since Yosemite includes AirDrop, you could also try airdropping those files to your newer MacBook–this should work.
I moved my photo library from my late 2012 Mac to an external LaCie HDD, with its own power supply. All went well.
Then when doing the same for my partner’s photo library, the Mac went to sleep.
The copy wasn’t finished (got a message that something went wrong), but worse, I can’t get the Mac to see the External HDD in Disk Utility, Finder, About this Mac -> storage or on the Desktop.
Even after trying all your steps. The only thing I did find out is that when I plug the USB in slowly, then under System Info -> USB I can see te Lacie connected. Plug it in fast, and it won’t show.
Strange thing is when it does show under USB3.0, it doesn’t show under System Info -> Storage (or Disk Utility/Finder/Desktop).
When I first moved my photo library, all was well and it did open from the external LaCie, right after moving it.
The Mac has no problem on the USB ports when connecting my iPhone or the WD MyPassport HDD I use for Time Machine backups (this one wasn’t connected during all the troubleshooting).
My laptop was stolen at an airport last weekend and I was forced to buy a new MacBook.
I was trying to avoid the models that had USB C ports, but here we are.
I purchased an adapter so that I could plug in my external hard drive. The drive lights up but is never recognized on the new mac.
I’ve trouble shooted at a basic level and I’m not sure what else to do. My last MacBook (with relevant ports) had no issues recognizing this hard drive last week.
I hope you can help– my whole life is on that drive :/
Totally understand your situation–been there, done that!
Does the drive power up from the USB port or does it have its own power source?
I’m thinking that the drive might not be getting sufficient power–so if you can plug it into its own power source, try that and see if it makes a difference.
It’s also possible there is a problem with that adapter or the USBC port itself. You’ll need to test the adapter and the port to figure this out.
When you plug in the adapter, it should click in–not be loose. If it’s loose–it may need a repair or replacement.
If this is all too much, try connecting that drive to someone else’s Mac and see if it’s recognized and appears. You can even go to an Apple Store and ask them to connect your drive to a Mac to test its functioning.
Great info but did not solve my problem and I got totally lost trying to make sense of Console … it’s a foreign language with no guidebook.
High Sierra on my Mac detects and mounts ext (Time Machine) drive on full Start-Up and Login.
However, if Mac has been only logged out rather than shut down, then at Login the drive is detected but not mounted (you can see it listed in Disk Utility but greyed out).
At this point it responds to a manual re-mount and then functions as expected; but it used to work properly.
It seems that something has inadvertently happened while browsing or I have accidentally clicked on something affecting system setup.
In trying to solve this problem I resorted to resetting the hard drive, doing a full-Time Machine backup from scratch and then full encryption.
It took days and has not solved the problem.
I suspect a corrupted keychain access or a background app (Malwarebytes?) gobbling up resources and clogging up system resources during login, effectively causing the mounting process to be skipped.
Yes, Console is difficult! You are not alone in that.
There was a big in High Sierra back in 2018 that impacted mounting some external drives. Have you updated to the latest version of macOS High Sierra or considered updating to Mojave? Some readers found that updating to macOS Mojave solved any problems with mounting external drives.
If that’s not an option you’re willing to take right now and you suspect that there is some malware interfering, take a look at running Malwarebytes and see if anything shows up.
You should also run Apple Diagnostics to see if there is any hardware issue at play. Restart your Mac and press and hold the D key on your keyboard. Keep holding that D key until you see a screen asking you to choose your language, the release.
One of my external drives decided was not going to show up on my Mac. It would not mount. I tried every thing in this article spending hours trying to get it to mount. It just could not be found by disk utility or or the terminal. You could see it but it just would not respond. Till I got to the bottom of the article it was suggesting I recover the info on the drive using a software called Stellar Data Recovery. Once I downloaded this (free version) and started to run it low and behold I noticed that my drive showed up on the desktop. I could even open it up the and see all my files. I had about 6 Photo libraries some from iPhoto years ago. And I had folders with 1000s of photos I did not want to loose. This was the only thing that worked to get my drive back. My mistake was disconnecting usb cables to move some things around without first ejecting the drive. This did not effect my other drives but just this certain one. My suggestion to everyone is to remember to eject before pulling the usb connectors off the computer.
Hi, I’ve dropped my external HD and the device still works without any weird noise but I’m not able to see any data, is there any of those procedures would help without losing my data. Thanks in advance
Have you tried Disk Utility? Does it see your drive and the info on it? If Disk Utility sees your drive, try running First Aid on it and verify/repair the disk if possible.
It’s also possible that the drive itself is okay but the enclosure is somehow broken. In that case, remove the hard drive from its current enclosure and place it in another enclosure–then see if your Mac recognizes it.
If that sounds confusing, take your external drive to an Apple repair shop (does not have to be an Apple Store shop or Apple Support shop–just a shop that fixes Apple products) and ask them to take out your disk and check it using another enclosure.
It’s equally possible that your data is okay or corrupt. We hope its okay!
Hi, I have an old MacBook Pro SSD (2013-14 I think, its 12+16 pins) that I am trying to get the data off of.
I currently have the MacBook Pro from 2018.
I purchased an external enclosure and installed the old SSD into it.
When I plug it into my Macbook, the lights on the external enclosure turn on, but my Macbook does not detect it.
I plugged the external enclosure into my PC and it came up with the information about the SSD like capacity, and how full it was, but I couldn’t access any files because it is formatted for a Mac.
I tried all of the steps above, and still no luck. Any suggestions on what’s next for me?
Have you tried another Mac–possibly an older Mac that runs Mac OS X instead of macOS Mojave/High Sierra? Make sure you connect the drive to a port on the Mac directly–not via a hub.
We’ve seen several reader reports of problems with external drives and macOS Mojave or High Sierra that use the new Apple file System (APFS).
a different USB cable
a different USB port
turn off the computer AND your external hard drive. Power up the drive FIrST and then restart the
computer
try a different Mac
Thanks so much for all of this info! I have been working down the list and when I went into Console it says ‘Connection invalid’ on Stores connection. Any advice on where to from here?
First, restart your Mac. This error is often temporary.
Are you able to open the Mac App Store–this connection invalid error means that you should not be able to open the App Store at all. So see if you can.
If you cannot open the Mac App Store, let us know so we can assist further.
It’s really strange that Super Slow Jam is working flawlessly for me, super thanks. I’ve tried to change usb cable, change usb port, plug into different computers, but none of those things worked for me.
Después de intentar todo lo que leí en este blog , me decidí a desmontar la cajita donde el servicio de apple me puso el disco duro antiguo; comprobando que hacia mal contacto pues el conector estaba suelto y unas veces iba bien y otras no (faltaban unos tornillos de sujección).
Ahora va de cine; ósea perfecto.
In English: After trying everything, I decided to look at the insides of my old hard drive. I checked the contacts and sure enough, the contacts were bad because the connector was loose. Sometimes it worked and sometimes it did not. Ultimately, I discovered that there were screws were missing.
Hi I have an Buffalo external hard drive Model HD-LBU2. connected via usb. it is from my windows pc and all I would like to do is transfer my photos from this HD to my new Mac. problem is, I cannot find or see the HD on my Mac anywhere. All the usb’s are working fin Thanks
Sorry that your Mac is not recognizing your Windows’ PC external drive. First thing is to restart your computer. If after the restart, your drive isn’t showing up still, open Disk Utilities and check if that sees the drive. If so, try and mount it.
If that doesn’t help, let’s try some Terminal commands:
diskutil list
This command shows the list of all connected drives. If your external drive shows up, take note of the number. Look for /dev/disk_
Next type in this command to force the disk to mount (put the disk number where the underscore is at the end)
When i type diskutil list, my external hard disk appears as /dev/disk2 (external, physical)
However, when Im trying to mount my disk, this message appears
Volume on disk2 timed out waiting to mount
[Process completed]
Here’s a fun one for ya…
2011MBP, Yosemite. A long time ago, I changed a bunch of system icons manually by moving the original/backups and replacing them with my new versions (yes, this was when I knew just enough to be dangerous, apparently), but couldn’t find some drive icons. Then, I thought I got smarter and used a 3rd party app (LiteIcon) to replace the drive icons as well. A little while after that (if I remember correctly, it was after the update to Yosemite), my USB ports stopped recognizing external drives unless I shut down the machine and START UP again with the USB drive PLUGGED IN (could do so through reset as well if timed right). Apparently, this was because LIteIcon replaced files directly in the extension bundle. This caused the signature to differ from what the system was expecting, so it wouldn’t load the extension.
It took me a LOOOONG time and a LOT of aggravation to finally sort it out. Luckily the solution is fairly simple, and involves changing icons back to normal. *POOF!* External drives work again!
Just wanted to pass that along in case anyone else out there is stuck trying to figure it out.
That’s awesome! Thank you so much for sharing your adventure in sorting out the problems with your MacBook. We’ll add this into our Reader Tips–it surely will help others. Always great to hear what works (…and what doesn’t).
My USB port was working fine yesterday…but now trying to plug in anything is impossible. Comparing it to my 2nd USB port, it looks less deep, as if the end came loose and got stuck. I can’t physically plug anything in comepletely and thus it cannot be read. I tried to push down on it gently but it wouldn’t budge. Any idea how to fix this? Thanks.
Oh my goodness, what a pain! Have you inspected that port with a flashlight to ensure that there is not anything stuck inside the port? We’ve had occasional reports of USB sticks or cable ends coming off inside the port–and thereby blocking it.
It’s also possible that the USB port has either become loose or worn–there are scattered user reports of this happening on MacBook Pros (and some MacBooks) from 2016-2018.
If your Mac has AppleCare or is under the limited warranty, seek out assistance immediately and request a repair now (before your AppleCare expires.) If you do not have AppleCare, it’s still worth bringing it to Apple’s attention.
Telephone support is free for 90 days with a new Mac or for three years with AppleCare
Set-up an appointment at the Genius Bar at your local Apple Store for hardware evaluation and assistance (Genius appointments are free–those parts and labor to fix are not unless covered by AppleCare or if you make a strong and insistent case)
I have a MacBook Pro from 2012 and an external hard drive (Samsung portable something…). I had it plugged in today and it worked just fine. Then, as I was moving my computer the hard drive fell down (still plugged in). It didn’t hit the floor but it hit one of the legs of the table. It didn’t seem like such a hard hit though. After a little while I heard a ticking noise from the hard drive and tried to eject it, but the computed refused to do that, so I pulled it out without ejecting. Now when I try to insert it again it makes a short noise for a few seconds (kind of sounds like an alarm but very quiet) and the little blue light on the hard drive shines, so I know there is some kind of connection, but it doesn’t show up on my mac anymore. I’ve tried svereal times in both USB-ports and I’ve also tried restarting my computer and nothing has worked yet. Any idead on how to fix this?? 🙁
Sorry to hear about your external drive. That ticking or clikcing noise is often an indicator that the something is seriously amiss with the drive heads. The blue light you see may indicate that power is reaching the drive but its not able to read the drive or the read/write heads are out of allignment and don’t know where to go. What you can do is let the drive rest, unplugged without access to power for a few hours and then try again. But only try this once–trying to access a clicking drive repeatedly will actually make things worse. Once you plug the drive back in, open Disk Utility and see if it recognizes the drive at all. If so, try First Aid.
If the resting period doesn’t work AND that drive contains vital data, it’s best to contact a repair shop immediately and have them inspect the drive. They may be able to recover its data and place it on a new drive.
Once you hear that clicking sound, it’s best to replace the drive–even if it starts working again. There is a high probablity of future failure.
Hi I am trying to follow the instructions you have using terminal as my external hard drive does not show up under disk utility or storage, but does show up in my system report. Anyway I got as far as the diskutil eject disk3 command but it keeps telling me “volume times out while waiting to eject”. Do you have any advice on what to do from here?
Try these commands. I’m using disk3 as the identifier per your message–verify that your external HD is indeed disk3 before proceeding with these Terminal Commands.
Sorry you’re having issues with an external disk. Let’s see what we can do today to help out!
Try this additional Terminal command: diskutil list
Then locate the exact disk identifier (look for /dev/diskx) where x is the disk number
Then try running:
diskutil eject /dev/diskx
diskutil mount /dev/diskx
Replace /dev/diskx with your unique disk identifier.
And if even that does not work, try this command to see the disk as read-only
diskutil mountDisk readOnly /dev/diskx
If it mounts, eject it using Finder and then physically unplug the usb cable from the drive. Restart your Mac and plug the USB cable back into your Mac and see if it shows up as Read/Write.
If read doesn’t work, try this command to verify and repair (if necessary):
diskutil verifyDisk /dev/diskx
Again, replace /dev/diskx with your unique disk identifier.
If the problem persists, let us know!
SK
You can also use Disk Utility to verify and repair the disk (Application > Utilties)
i’m having the same problem and it is failing when i try to do the read only command.
IMsays
My external drive stopped mounting this evening after my MacBook went to sleep just a few seconds after it had woken up. I’ve tried the steps above as well, and got to the point of applying the, “diskutil verifyDisk /dev/diskx” command. Butt the response I get back is, “Unable to verify this whole disk: A GUID Partition Table (GPT) partitioning scheme is required (-69773)”
Please advise what additional steps I might take at this point.
Kind regards,
IM
Miasays
Hi! These are the messages that appeared on Console when I plugged in my external HD:
The device is still unresponsive after 6 consecutive USB Device Resets; it will be terminated.
Sorry, you’re having issues with your Mac not recognizing your external drive. Please remove the drive then shut down your Mac, wait a few minutes, and then restart. Wait for your Mac to fully restart, then open an app (any one app will do) to make sure the computer is responsive. Then insert the external drive into a DIFFERENT USB PORT (if possible) using the Slow Jam method (plug it in very slowly), see if the Mac recognizes the drive.
If that doesn’t work, go through the same process using a different USB port each time, if available. IF still nothing, ask a friend or family member (or workplace/school, even an Apple Store) who has a MAc and see if their Mac recognizes the device. If so, copy that information onto a drive that your Mac does recognize. Then reformat the external drive and test on your Mac again.
I’m new to Mac, so was a little confused with some instructions but tried the slow jam as it was a simple process and by golly it worked! Thanks a lot.
Thank you, Elizabeth, for writing up this list. I’ve been frustrated for months with my SanDisk USB 3 thumb drive not mounting after I ejected it or after the computer was put to sleep–and I had to resort to rebooting my MBP 2015 to mount it. But Slow Jam works overtime! Amazing!
It worked for mw thew first time, then i turned off my macbook pro 2019 with the touch bar model, turned on agaiun, and is not recognizing the external disk anymore, it mount it perfectly in disk utility, it displays like mounted, first aid sais its working fine, but i cannot see my disk in the desktop, i turned on and off the checkbox in finder preferences and reseted the NVRAM, also terminal stuff… nothing seems to work, not even the slow jam 🙁
WD Mybook unrecognized by Powerbook OS 10.9.5, finally got error message that drive could not be accessed, and opened Disk Utility with error window still onscreen. Repair didn’t work, but I was able to Erase the 4 terabyte drive and the software recognized disc. Now backing up with Time Machine, seems to be functioning normally.
Also, you might reset the System Management Controller (SMC.) See these steps under the section “Does Your MacBook Shut Down When You Plug In Your External Hard Drive?”
I have a mid 2012 MacBook Pro 13 inch. I am trying to connect a USB-C SSD via an apple USB-C to Thunderbolt 2/3 adaptor and an apple thunderbolt 2/3 cable to the thunderbolt port . The SSD is not at all recognised.
It is recognised via the usb 3 port. I would however like to take advantage of the faster speeds of the thunderbolt port?
Any feedback would be appreciated.
Thanks
I have a Acer cheapo laptop running Windows 8…never, ever had a problem recognising drives etc. updates to latest Firefox runs well (Mountain Lion can’t run anything anymore as the Bible says : ‘better to be a live dog then a dead lion’) and fast (ssd only 4GB of ram, i5) My iMac, same age can’t run anything unless it has the right yearly released stupid MacOS ( 9 different ones in as many years compared to Window 2!) I only use Apple rubbish for Logic software. They are badly made, their operating system is cumbersome at best, clumsily designed, not intuitive. I’m trying to upgrade a Mountain Lion OS to El Capitan (who thinks up this silly primary school nonsense?) Won’t see external HD, download this, research that. One week in and still working on it. Artificial Intelligence? Do me a favour we can’t even get passed Artificial stupidity, designed by morons who live a silicon vally bubble. Now, rant over. Apart from that everything is fine and the iMacs still ain’t able to browse the internet. Happy days.
Nowhere is mentioned the strict, by-design incompatibility of MacBook pro circa 2012 that has an internal superdrive (obviously non-functioning so as to need an external) with the Apple External SuperDrive!
And nowhere do you identify other, non-APPLE external optical drives that would work with the beleaguered 2012 MacBook pro.
(I would rather not take the chance of corrupting the terminal and making my computer as non-functional as the internal drive).
Thank you so much for this article! My 2017 MacBook Pro suddenly decided it wouldn’t detect the charging cable – which was a bit of an issue with only 20% battery power left. I thought it was probably a battery issue but then it wouldn’t detect a back-up disc either. Rest the SMC as outlined above and Bob’s your uncle – all working again!
Worked for me by unticking all boxes in spotlight. Thanks Elizabeth, it was really helpful. Did not find this advice anywhere else.
I’m about to give up with my Mac!
Originally I copied complete hard drive, videos, docs, pics, music onto an external no problem.
However since then it has never recognised it at all.
Also I reformatted another external to backup, same thing never recognises it.
Absolutely useless & wasted hours trying to find a solution.
Back to Windows!
I have a MacBook Pro late 2011 using ElCapitan 10.11.6. It has 2 USB 2.0 Ports and I have an Insignia 2.0 -7 port Hub, external power, attached to one built in hub and the other built in hub has a Passport 0748 2TB storage hard drive plugged in.
I have another D-Link 2.0 7 port hub, no external power plugged into one of the 7 Insigna ports.
I have Macintosh HD 1 TB internal drive.
I have 5 USB external drives, A Passport 0748 2 TB hard drive, A Passport 070A 1 TB hard drive, A Passport 2626 2 TB hard drive, a Seagate back up & desk 5 TB external power hard drive and a My Book 1234 2 TB external power hard drive.
Because I need to continue to use a Lion 10.7.5 system, the My Book 1234 is a 2TB Macintosh HD 10.7 bootable disk plugged into one of the D-Link ports and the Macintosh HD has the bootable 10.7.5 System. I needed to have a newer system to use my browsers and other new applications so the bootable ElCapitan system boot disk 10.11.6 is on the Passport 2626 which is plugged into one of the 7 Insigna Ports. That is ElCapitan disk boot system I am presently using. The Passport 070A, 1TB hard drive is plugged into one of the 7 Insigna ports is used for storage and is not bootable. The Seagate 5TB back up & desk is my back disk and is plugged into one of the 7 D-Link ports. Finally, the Passport 0748, My Passport 2 TB disk is a main document storage disk plugged into the 2nd built in USB 2.0 port. This My Passport 2 TB disk is visible on the System Information USB tree but is not visible on the Disk Utility list nor the desktop of the ElCapitan system.
I have plugged the My Passport into every built in port and in to ports on the Insigna 7 port hub and the D-Link 7 port hub. It always shows up on the System Information USB tree, but never shows up on the Disk Utility. I have plugged it in fast…I have plugged it in slow, I have plugged in and re-booted, I have plugged it int to all hub ports after re-booting, I have unplugged it and replugged it in. It never shows up… Ever.
This disk contains all my engineering and surveying documents over a period of 30 years. It was working very well, but I have recently been shutting my computer completely off at and in the morning boot up (off the Passport 2626 ElCapitan disk, sometimes all of the passport disks will not work and the computer defaults and boots up off the internal disk. The external power disks Seagate and My Book 1234, Macintosh HD 10.7 always are visible as is the internal Macintosh HD disk.
Usually the visibility can be overcome by just plugging and unplugging in the disks or plugging them directly into the built in port. If any of the passport disks are plugged to the built in ports when booting up they show up… EXCEPT the Passport 0748 My Passport disk. It only shows up on the System Information tree.
The oldest external disks are….. in order, oldest first… Seagate, My Book, Passport 0748, Passport 070A and Passport 2626 (new). The built in hard drive is the oldest of all.
How do I get this disk to mount so I can use it to transfer information to another new disk?
Hi Rex,
Sorry to hear about your problems with your Passport drive. It sounds like you exhausted a lot of troubleshooting options.
Have you tried plugging the Passport into another Mac to see if it mounts? If not, I would give that a try to see if it’s the Disk that’s the problem or something on your Mac.
Hi
Recently updated to high sierra on an old mac, (yes I am that behind with updates!), now it won’t let me access a Samsung Hard drive i used to use.
It won’t mount using disk utility.
I can see it using the Terminal and have ejected it like you said, however even though it says ejected, and the light on the hard drive turns off, it is still listed when I type diskutil list. When I plug in again, it still won’t let me access it (nothing appears in finder).
Any ideas please?
I tried the erase option to rewrite it from NTFS to exFAT, did this remove everything that was on the disk…?
Ok – just for kicks, I tried the Slo-Jam and…. IT WORKED.
Hello!
I am having these issues where my hard drive (that has previously connected well) is not showing up!
When I go to disk utilities, the page never loads so I can’t remount it if that is the issue.
I was wondering if I unplug it from my computer without ejecting (since my computer isn’t even reading that it’s plugged in) if it will corrupt my hard drive?
I do not want to lose all the photos I have on it, however I don’t want to just leave the drive plugged in if it is not showing up.
Thank you!
Hi Sydney,
Disk utility should show up and populate.
Can you access the Terminal app? If so, instead of unplugging the drive, try mounting the drive via a terminal command.
1) open Terminal from your Utilities folder
2) type in the command diskutil list
3) see if that external drive shows up in that list. If so, take note of how it’s named (listed as /dev/disk# external, physical)
4) try mounting it using command mount /dev/disk#
5) if that doesn’t work, try a forced mount using command mount force /dev/disk#
Hi Liz,
I have a MacBook Pro 2016 and a my passport for mac hard drive which stopped mounting. I have done pretty much everything you suggested including terminal- force mounting (does detect before that) – comes up with unknown special file or file system message. In console – not sure how Hard drive specific errors would look like.
It is coming up in disk utility (in grey) but no first aid or mounting is working.
Any other ideas that could work for troubleshooting?
Cheers
Cris
After installing the latest update macOS High Sierra V 10.13.6 my laptop will not eject the disk using Terminal commands. I receive a response that It “timed out”
Command used was diskutil eject disk3
I’m doing this because the external drive only shows in Terminal; when checking drives, it indicates the external hard drive is not mounted; and I’m unable to mount it.
I have a Macbook Pro 17-inch Mid 2010. Everything was working fine until the update was installed.
Why are Macs so terrible?
It feels like a half-finished program. How can they charge three times as much for something that works a tenth as well and then be considered anything other than crap?
I don’t get it. The biggest waste of money ever has been a Mac, spend $4,000 for a computer that does half the stuff in twice the time, and has another problem with each update.
Just junk.
I had to pull out an old Windows PC and do the work on it because it sees the hard drive perfectly.
Congratulations to whoever wrote this, as a person who used to write guides for the use of a govt agency crash system these instructions are excellent , simple , great use of screen shots and written in a friendly not too technical way. 10/10
Hi I have an external hard drive and suddenly my mac stops reading it. There is no icon on the desktop. Disk functions ok with other pcs. When i go to Terminal and type diskutil info it appears there. What can i do to unblock this situation?
HI Michalis,
Try using Disk Utility (in Applications > Utilities) to mount the disk (you may need to verify it or run first aid) or use Terminal with the command: diskutil mount /dev/diskXXXX (where XXXX is your disk’s number as shown in diskutil list)
I have an issue with my MacBook, yes, it is that old. One day it is running slow, but working. Next day, I get a blinking file folder with a ?. I have been trying to restore, but it is not taking it. Been trying for 3 days. Yes, I am giving up…for now. I had to remove the internal hd to make it an external. It kept running the install disk, Snow Leopard, and it kept doing it no matter if I restored it or not.
Now, I no longer see the hd! I ran discutil but it is no longer finding it. What the hockey sticks happened and how do I fix it?
It shouldn’t be so complicated for a Mac to recognize a USB that was working before.
Spending hours trying to connect something to your computer is bonkers.
The amount of working time I am losing trying to do this is insane.
Moreover, I don’t have access to all my stored information.
I am really fed up with this.
Not even mentioning the supposedly superior Mac for photos that almost burn out every time I try and download the camera pictures to it. My 8-year-old PC worked better than this. Worst upgrade in a computer ever!
Me too…. I was directed by a senior Apple support advisor to the manufacturers of the several hard disks my Mac mini cannot read now….
Hello,
my imac 6.1 late 2006 does not recognise bootable FlashDrive for installing WIndows 10 with the help of bootcamp. Please advise how should I proceed to achieve the aim.
Slow jam…!!! yeah..!! worked like a charm..
Hello
What if the drive only flashes when plugged in no matter how you do it? Also it does not show up in disk utility.
Thank you SO much!
Hi Adam,
When the drive is flashing, it usually means your Mac is running through a series of check to mount the drive. And for some reason, it’s getting stuck in this process.
Try using Terminal to eject the disk, then shut down your Mac, wait 20-30 seconds and unplug the external drive from the Mac, and power your Mac back on. Wait for your Mac to fully boot, then reconnect the drive to your Mac and see if it now recognizes it.
1) open Terminal (in Applications > Utilities)
2) type in this command: diskutil list — this shows a list of all internal and external disks
3) locate your external drive in the list and find its identifier listed as: /dev/disk(#) where # is the disk’s number in your system
4) type in these commands to eject your external drive: diskutil unmountDisk /dev/disk# followed by the command: diskutil eject /dev/disk# make sure you replace # with the number of your external disk as listed in your system disk list
After ejecting, shut down, power back up, and connect the drive after fully booted.
If this doesn’t work, let us know.
Liz
I was having the same problem, and tried the diskutil in Terminal. My disk still doesn’t appear here either. Do you have any other suggestions? Thanks in advance for your help!
Hi Paige,
Depending on how you formatted the drive, see if you can use someone else’s computer temporarily and see if it picks up your drive.
Hello!
I have an external lexar ssd 512mb that I usually use on my MacBook Pro. Suddenly yesterday when I restarted my laptop the disk stop showing up. I tried disk utility but the lexar is not showing up too. in my laptop I’m using mojave about quite a time. I tried the console and not showing up.
Then I connect the drive to my old iMac with Sierra, and the disk mounts and shows up. Tried to format again, only appears on Sierra and not mojave.
Also appears in windows but not mojave.
Does anyone has a solution?
Thanks.
Hi Elizabeth
I recently purchased a 1Tb External SSD hard drive to use on my Macbook Pro and iMac.
When I plug the drive in the computer tells me it is unable to read the disk and I’m presented with the Dialog box asking me if I’d like to initialize or eject the disk.
When I choose Initialize I get the Error “Disk Erase failed with the error: “Unable to write to the last block of the device”.
I read one of your answers to a previous post and used Terminal to inspect the disk.
Terminal tells me the disk is Unformatted.
Any advice would be much appreciated,
Regards
Dave
Hi Dave,
Sorry about your troubles with your external drive.
Was the drive you purchased for a Mac or Windows or unformatted?
Also, what format are you choosing to initialize the drive with? The current recommendation from Apple is Mac OS Extended (Journaled) not APFS, FAT, or exFAT.
If you purchased it for Mac and it’s not recognizing it, I recommend you return the drive to the place of purchase or contact the manufacturer. That drive (for Mac) should work out of the box with no formatting required. Since it isn’t working, I would be skeptical about long term performance and stability, even if you are successfully able to reformat it.
You could try using a different cable and/or port on your Mac–sometimes we see these types of error when there is a problem communicating.
Another option is to launch into Recovery Mode (Command+R) and open Disk Utilities from there to format the drive. It might work.
All in all, the fact that a new drive is giving you these errors makes me suspicious that it won’t perform well over the long term–so if you can return it or replace it, do so now.
Keep me posted,
Liz
Hi, many thanks for all this great info. Unfortunately, my WD Passport USB external hard drive is being particularly stubborn. I’ve tried your suggestions, bought a new cable and tried other macs but still no luck.
The hard drive powers up normally with no weird noises and has a continue white light (no flashing) and as far as I can see all is normal. But for some reason, it is not showing up in Disk Utility, Terminal or Console.
It’s functioning but invisible????
Hi Daryl,
Sorry about your external drive troubles.
Can you see the drive when you check your System Report on your Mac?
Go to Apple Menu > About this Mac and tap System Report.
Thanks for getting back to me. It’s greatly appreciated! Unfortunately, System Report is only showing Apple Internal Keyboard/Trackpad, BRCM20702 Hub and Bluetooth USB Host Controller 🙁 Many thanks for your suggestion!!
.
Hi Daryl,
You bet. Sorry, that didn’t show anything.
You mentioned you tried this on other Macs as well and the drive didn’t show up either–correct? If you have quick access to another Mac, I would try connecting the drive and see if another Mac picks up the drive using System Report or elsewhere.
Also, before connecting the drive to your Mac or any other:
1. Close all apps
2. Shut down the Mac
3. Once powered off, connect the drive and if available, connect the drive to its own power source
4. Power up the Mac
5. Remember to try multiple ports on the Mac–just in case there is a problem with a port
If the problem replicates on another Mac, then the problem is likely some hardware issue in the drive itself–perhaps a loose cable or some other issue. In that case, you can either take the drive itself into a repair shop OR if you like tinkering around DYI, then you can open up the drive’s case and take a look for any obvious problems, like a lose or detached internal cable.
Keep us posted,
Liz
Hello, I read this article, you described so deeply. As you said “There are several reasons why Mac won’t recognize a drive. If disk already mounted and system goes to sleep, it also powers down ports, including USB ports. When you wake your Mac up, for whatever reason, your external drive does not wake up”.
It is right because generally sometimes an external hard drive doesn’t show up on Mac. It is very bad when you need to transfer something right then. It can be risk that on the external drives which means you cannot transfer what you need between devices at all.
I did not know why this happen then I searched and found that it happens because multiple reasons like faulty cable, damage USB port, file system corruption, and so on. But if external drive’s data is not accessible due to file system corruption then it can be cause of data loss.
One more point, I would like to share about data recovery software. During research I found that there are software available online that are very helpful if some lost data during this update, they can recover easily. I read reviews and most of them suggested Stellar Data Recovery. I used free demo to check and found better result.
But, I am wonder to read this blog because of you described a so many tips or solutions to fix it which I did not know. Very useful article for me I personally believe. Thank you so much.
I struggled for over a year with failure-to-mount my Time Machine external disk on MacOS (10.11).
I knew the drive and cable were okay. A reboot would always fix, but who wants to do that every few days?!
I tried all kinds of advice from these sites and forums; wasn’t fsck; resetting SMC had no effect; nothing but a restart seemed to work.
Then when the same problem immediately appeared on a new/second Time-Machine disk of different make, I finally tried a stupid-lame trick of switching USB ports.
“Okay,” it says! I can’t predict which of the two ports will work on any given attempt (still new to the trick and have not nailed down a pattern).
But so far if one port fails, the other works (swapping roles).
Bizarre, and still annoying.
But it’s looking like I won’t have to keep rebooting so often.
Thanks for this discussion.
It is the first one which talked about what I am sure is my issue, namely power and recognizing external disks with a port expander.
My situation is that I have 3 USB disks connected to my High Sierra based Mac using an Ankar powered port expander.
On my older Mac running macOS Sierra, this was not a problem.
But now with my new Mac Pro connected through the new Thunderbolt connector, not all of the disks mount when I turn the computer on.
Sometimes none, sometimes several.
Unplugging the various disks and reconnecting them eventually gets them all to work, but there is no procedure I have worked out that reliably gets them all to mount.
If anyone who has experienced this problem has found a permanent solution I would be interested, even if I need to buy a different port expander.
Hi Knox,
Sorry, your Mac has issues with your hub.
A lot of readers notice issues with their older hubs working on macOS Mojave.
We suggest you check out this Apple Shop page where they list the hubs they sell and recommend for Macs.
You don’t have to purchase from Apple–just make a note of the make and model for the hub and if desired, purchase elsewhere.
Liz
good morning.
I have a Toshiba Canvio external hard drive that works fine on MacBook pro-2015 Yosemite, but when I try to use it on my new MacBook Pro-2018 Mojave it doesn’t recognize.
I see it grayed out in Utilities and I just need to know if I try to mount it there will I lose my files?
I have important files in it and can’t risk losing them.
Thanks for your help
Hi Susan,
We suggest you NOT mount it on the MacBook Pro with Mojave since it is not auto-recognizing that drive.
It should see it, but since it isn’t and you mention it has very important files, then leave it.
What we do suggest is purchasing or borrowing an external drive that does work with your new MacBook Pro and then duplicating those important files onto that drive using your older MacBook.
Since Yosemite includes AirDrop, you could also try airdropping those files to your newer MacBook–this should work.
Keep us posted,
Liz
I moved my photo library from my late 2012 Mac to an external LaCie HDD, with its own power supply. All went well.
Then when doing the same for my partner’s photo library, the Mac went to sleep.
The copy wasn’t finished (got a message that something went wrong), but worse, I can’t get the Mac to see the External HDD in Disk Utility, Finder, About this Mac -> storage or on the Desktop.
Even after trying all your steps. The only thing I did find out is that when I plug the USB in slowly, then under System Info -> USB I can see te Lacie connected. Plug it in fast, and it won’t show.
Strange thing is when it does show under USB3.0, it doesn’t show under System Info -> Storage (or Disk Utility/Finder/Desktop).
When I first moved my photo library, all was well and it did open from the external LaCie, right after moving it.
The Mac has no problem on the USB ports when connecting my iPhone or the WD MyPassport HDD I use for Time Machine backups (this one wasn’t connected during all the troubleshooting).
Any ideas? I’m stuck.
Hi there,
My laptop was stolen at an airport last weekend and I was forced to buy a new MacBook.
I was trying to avoid the models that had USB C ports, but here we are.
I purchased an adapter so that I could plug in my external hard drive. The drive lights up but is never recognized on the new mac.
I’ve trouble shooted at a basic level and I’m not sure what else to do. My last MacBook (with relevant ports) had no issues recognizing this hard drive last week.
I hope you can help– my whole life is on that drive :/
Hi April,
Totally understand your situation–been there, done that!
Does the drive power up from the USB port or does it have its own power source?
I’m thinking that the drive might not be getting sufficient power–so if you can plug it into its own power source, try that and see if it makes a difference.
It’s also possible there is a problem with that adapter or the USBC port itself. You’ll need to test the adapter and the port to figure this out.
When you plug in the adapter, it should click in–not be loose. If it’s loose–it may need a repair or replacement.
If it’s the USBC port that’s the problem–contact Apple Support or setup an appointment at your Apple Store.
If this is all too much, try connecting that drive to someone else’s Mac and see if it’s recognized and appears. You can even go to an Apple Store and ask them to connect your drive to a Mac to test its functioning.
Inserting the external hard drive cable slowly into the macbook worked for me too. Quite Strange…. but worked !
Great info but did not solve my problem and I got totally lost trying to make sense of Console … it’s a foreign language with no guidebook.
High Sierra on my Mac detects and mounts ext (Time Machine) drive on full Start-Up and Login.
However, if Mac has been only logged out rather than shut down, then at Login the drive is detected but not mounted (you can see it listed in Disk Utility but greyed out).
At this point it responds to a manual re-mount and then functions as expected; but it used to work properly.
It seems that something has inadvertently happened while browsing or I have accidentally clicked on something affecting system setup.
In trying to solve this problem I resorted to resetting the hard drive, doing a full-Time Machine backup from scratch and then full encryption.
It took days and has not solved the problem.
I suspect a corrupted keychain access or a background app (Malwarebytes?) gobbling up resources and clogging up system resources during login, effectively causing the mounting process to be skipped.
I would love to solve this problem. Any ideas?
Hi Simon,
Yes, Console is difficult! You are not alone in that.
There was a big in High Sierra back in 2018 that impacted mounting some external drives. Have you updated to the latest version of macOS High Sierra or considered updating to Mojave? Some readers found that updating to macOS Mojave solved any problems with mounting external drives.
If that’s not an option you’re willing to take right now and you suspect that there is some malware interfering, take a look at running Malwarebytes and see if anything shows up.
You should also run Apple Diagnostics to see if there is any hardware issue at play. Restart your Mac and press and hold the D key on your keyboard. Keep holding that D key until you see a screen asking you to choose your language, the release.
One of my external drives decided was not going to show up on my Mac. It would not mount. I tried every thing in this article spending hours trying to get it to mount. It just could not be found by disk utility or or the terminal. You could see it but it just would not respond. Till I got to the bottom of the article it was suggesting I recover the info on the drive using a software called Stellar Data Recovery. Once I downloaded this (free version) and started to run it low and behold I noticed that my drive showed up on the desktop. I could even open it up the and see all my files. I had about 6 Photo libraries some from iPhoto years ago. And I had folders with 1000s of photos I did not want to loose. This was the only thing that worked to get my drive back. My mistake was disconnecting usb cables to move some things around without first ejecting the drive. This did not effect my other drives but just this certain one. My suggestion to everyone is to remember to eject before pulling the usb connectors off the computer.
Hi, I’ve dropped my external HD and the device still works without any weird noise but I’m not able to see any data, is there any of those procedures would help without losing my data. Thanks in advance
Hi Ricardo,
Have you tried Disk Utility? Does it see your drive and the info on it? If Disk Utility sees your drive, try running First Aid on it and verify/repair the disk if possible.
It’s also possible that the drive itself is okay but the enclosure is somehow broken. In that case, remove the hard drive from its current enclosure and place it in another enclosure–then see if your Mac recognizes it.
If that sounds confusing, take your external drive to an Apple repair shop (does not have to be an Apple Store shop or Apple Support shop–just a shop that fixes Apple products) and ask them to take out your disk and check it using another enclosure.
It’s equally possible that your data is okay or corrupt. We hope its okay!
Good luck,
Sam
Thanks! This post helped solve the issue.
Hi, I have an old MacBook Pro SSD (2013-14 I think, its 12+16 pins) that I am trying to get the data off of.
I currently have the MacBook Pro from 2018.
I purchased an external enclosure and installed the old SSD into it.
When I plug it into my Macbook, the lights on the external enclosure turn on, but my Macbook does not detect it.
I plugged the external enclosure into my PC and it came up with the information about the SSD like capacity, and how full it was, but I couldn’t access any files because it is formatted for a Mac.
I tried all of the steps above, and still no luck. Any suggestions on what’s next for me?
Hi Jonathan,
Have you tried another Mac–possibly an older Mac that runs Mac OS X instead of macOS Mojave/High Sierra? Make sure you connect the drive to a port on the Mac directly–not via a hub.
We’ve seen several reader reports of problems with external drives and macOS Mojave or High Sierra that use the new Apple file System (APFS).
Hello
I am happy to seek out so many helpful infⲟ here іn the post about getting my Mac’s external HDs to work, thanks for sharing. . . .
Trying a super slow jam really worked for me!!! Thanks for that great and interesting advice!!!
Hi there
I tried everything in this article.
I used terminal and when I tried to eject the disk it says timed-out waiting to eject.
All my data is on this Toshiba external 1 TB drive which cannot be mounted, ejected etc by my Macbook air.
PLEASE HELP ME.
Try the following:
a different USB cable
a different USB port
turn off the computer AND your external hard drive. Power up the drive FIrST and then restart the
computer
try a different Mac
Or use terminal commands:
diskutil unmountDisk /dev/disk_
diskutil eject /dev/disk_
the underscore is the system number for your external disk
Super slow jam works!!!!!!!!!!!!!!!
**** Jobs, Gates and the whole industry who makes the life of all users (PC, Mac or both at the same time)!!!!!
Excelent instructions thanks a lot !
Thanks so much for all of this info! I have been working down the list and when I went into Console it says ‘Connection invalid’ on Stores connection. Any advice on where to from here?
Hi Melinda,
First, restart your Mac. This error is often temporary.
Are you able to open the Mac App Store–this connection invalid error means that you should not be able to open the App Store at all. So see if you can.
If you cannot open the Mac App Store, let us know so we can assist further.
Sam
thanks! plugging the usb connector in very slowly suddently made my external hd drive get recognized. itworks
This was very helpful, thank you
Thanks for this article.
It’s really strange that Super Slow Jam is working flawlessly for me, super thanks. I’ve tried to change usb cable, change usb port, plug into different computers, but none of those things worked for me.
Después de intentar todo lo que leí en este blog , me decidí a desmontar la cajita donde el servicio de apple me puso el disco duro antiguo; comprobando que hacia mal contacto pues el conector estaba suelto y unas veces iba bien y otras no (faltaban unos tornillos de sujección).
Ahora va de cine; ósea perfecto.
In English: After trying everything, I decided to look at the insides of my old hard drive. I checked the contacts and sure enough, the contacts were bad because the connector was loose. Sometimes it worked and sometimes it did not. Ultimately, I discovered that there were screws were missing.
Fix it and now my external drive works perfectly.
Hi I have an Buffalo external hard drive Model HD-LBU2. connected via usb. it is from my windows pc and all I would like to do is transfer my photos from this HD to my new Mac. problem is, I cannot find or see the HD on my Mac anywhere. All the usb’s are working fin Thanks
Hi John,
Sorry that your Mac is not recognizing your Windows’ PC external drive. First thing is to restart your computer. If after the restart, your drive isn’t showing up still, open Disk Utilities and check if that sees the drive. If so, try and mount it.
If that doesn’t help, let’s try some Terminal commands:
diskutil list
This command shows the list of all connected drives. If your external drive shows up, take note of the number. Look for /dev/disk_
Next type in this command to force the disk to mount (put the disk number where the underscore is at the end)
mount force /dev/disk_
If the problem persists, let us know.
Sam
Hi there!
When i type diskutil list, my external hard disk appears as /dev/disk2 (external, physical)
However, when Im trying to mount my disk, this message appears
Volume on disk2 timed out waiting to mount
[Process completed]
Please advise. Thank you.
Hi Joey,
Try these additional Terminal commands:
diskutil unmountDisk /dev/disk2
diskutil eject /dev/disk2
Then unplug your drive from your PC, restart the computer, and plug the drive back in. See if it now mounts.
SK
Here’s a fun one for ya…
2011MBP, Yosemite. A long time ago, I changed a bunch of system icons manually by moving the original/backups and replacing them with my new versions (yes, this was when I knew just enough to be dangerous, apparently), but couldn’t find some drive icons. Then, I thought I got smarter and used a 3rd party app (LiteIcon) to replace the drive icons as well. A little while after that (if I remember correctly, it was after the update to Yosemite), my USB ports stopped recognizing external drives unless I shut down the machine and START UP again with the USB drive PLUGGED IN (could do so through reset as well if timed right). Apparently, this was because LIteIcon replaced files directly in the extension bundle. This caused the signature to differ from what the system was expecting, so it wouldn’t load the extension.
It took me a LOOOONG time and a LOT of aggravation to finally sort it out. Luckily the solution is fairly simple, and involves changing icons back to normal. *POOF!* External drives work again!
Just wanted to pass that along in case anyone else out there is stuck trying to figure it out.
Hey Trav,
That’s awesome! Thank you so much for sharing your adventure in sorting out the problems with your MacBook. We’ll add this into our Reader Tips–it surely will help others. Always great to hear what works (…and what doesn’t).
Thanks again,
SK
My USB port was working fine yesterday…but now trying to plug in anything is impossible. Comparing it to my 2nd USB port, it looks less deep, as if the end came loose and got stuck. I can’t physically plug anything in comepletely and thus it cannot be read. I tried to push down on it gently but it wouldn’t budge. Any idea how to fix this? Thanks.
Hi C,
Oh my goodness, what a pain! Have you inspected that port with a flashlight to ensure that there is not anything stuck inside the port? We’ve had occasional reports of USB sticks or cable ends coming off inside the port–and thereby blocking it.
It’s also possible that the USB port has either become loose or worn–there are scattered user reports of this happening on MacBook Pros (and some MacBooks) from 2016-2018.
If your Mac has AppleCare or is under the limited warranty, seek out assistance immediately and request a repair now (before your AppleCare expires.) If you do not have AppleCare, it’s still worth bringing it to Apple’s attention.
Contact Apple Support
Chat online with a support team member (free)
Telephone support is free for 90 days with a new Mac or for three years with AppleCare
Set-up an appointment at the Genius Bar at your local Apple Store for hardware evaluation and assistance (Genius appointments are free–those parts and labor to fix are not unless covered by AppleCare or if you make a strong and insistent case)
Hope that helps,
SK
I have a MacBook Pro from 2012 and an external hard drive (Samsung portable something…). I had it plugged in today and it worked just fine. Then, as I was moving my computer the hard drive fell down (still plugged in). It didn’t hit the floor but it hit one of the legs of the table. It didn’t seem like such a hard hit though. After a little while I heard a ticking noise from the hard drive and tried to eject it, but the computed refused to do that, so I pulled it out without ejecting. Now when I try to insert it again it makes a short noise for a few seconds (kind of sounds like an alarm but very quiet) and the little blue light on the hard drive shines, so I know there is some kind of connection, but it doesn’t show up on my mac anymore. I’ve tried svereal times in both USB-ports and I’ve also tried restarting my computer and nothing has worked yet. Any idead on how to fix this?? 🙁
Hi Emilia,
Sorry to hear about your external drive. That ticking or clikcing noise is often an indicator that the something is seriously amiss with the drive heads. The blue light you see may indicate that power is reaching the drive but its not able to read the drive or the read/write heads are out of allignment and don’t know where to go. What you can do is let the drive rest, unplugged without access to power for a few hours and then try again. But only try this once–trying to access a clicking drive repeatedly will actually make things worse. Once you plug the drive back in, open Disk Utility and see if it recognizes the drive at all. If so, try First Aid.
If the resting period doesn’t work AND that drive contains vital data, it’s best to contact a repair shop immediately and have them inspect the drive. They may be able to recover its data and place it on a new drive.
Once you hear that clicking sound, it’s best to replace the drive–even if it starts working again. There is a high probablity of future failure.
Sorry about your drive,
SK
I just can’t believe!!!! The “Super Slow Jam” technic worked!! Thank you very much.
Obs.: I am using a macbook pro Early 2015 with El Capitan 10.11.6
Hi I am trying to follow the instructions you have using terminal as my external hard drive does not show up under disk utility or storage, but does show up in my system report. Anyway I got as far as the diskutil eject disk3 command but it keeps telling me “volume times out while waiting to eject”. Do you have any advice on what to do from here?
Hi AM,
Try these commands. I’m using disk3 as the identifier per your message–verify that your external HD is indeed disk3 before proceeding with these Terminal Commands.
diskutil unmountDisk /dev/disk3
diskutil eject /dev/disk3
Let us know if the problem persists,
SK
Slow jam worked for me. Who would believe that! Thanks
Hi I tried this solution.
diskutil unmountDisk /dev/disk3
diskutil eject /dev/disk3
It still does not work for me. It keeps giving me ‘Volume timed out while waiting to eject’.
Hi SW,
Sorry you’re having issues with an external disk. Let’s see what we can do today to help out!
Try this additional Terminal command: diskutil list
Then locate the exact disk identifier (look for /dev/diskx) where x is the disk number
Then try running:
diskutil eject /dev/diskx
diskutil mount /dev/diskx
Replace /dev/diskx with your unique disk identifier.
And if even that does not work, try this command to see the disk as read-only
diskutil mountDisk readOnly /dev/diskx
If it mounts, eject it using Finder and then physically unplug the usb cable from the drive. Restart your Mac and plug the USB cable back into your Mac and see if it shows up as Read/Write.
If read doesn’t work, try this command to verify and repair (if necessary):
diskutil verifyDisk /dev/diskx
Again, replace /dev/diskx with your unique disk identifier.
If the problem persists, let us know!
SK
You can also use Disk Utility to verify and repair the disk (Application > Utilties)
i’m having the same problem and it is failing when i try to do the read only command.
My external drive stopped mounting this evening after my MacBook went to sleep just a few seconds after it had woken up. I’ve tried the steps above as well, and got to the point of applying the, “diskutil verifyDisk /dev/diskx” command. Butt the response I get back is, “Unable to verify this whole disk: A GUID Partition Table (GPT) partitioning scheme is required (-69773)”
Please advise what additional steps I might take at this point.
Kind regards,
IM
Hi! These are the messages that appeared on Console when I plugged in my external HD:
The device is still unresponsive after 6 consecutive USB Device Resets; it will be terminated.
Device not responding.
Please help! What do I do next?
Hi Mia,
Sorry, you’re having issues with your Mac not recognizing your external drive. Please remove the drive then shut down your Mac, wait a few minutes, and then restart. Wait for your Mac to fully restart, then open an app (any one app will do) to make sure the computer is responsive. Then insert the external drive into a DIFFERENT USB PORT (if possible) using the Slow Jam method (plug it in very slowly), see if the Mac recognizes the drive.
If that doesn’t work, go through the same process using a different USB port each time, if available. IF still nothing, ask a friend or family member (or workplace/school, even an Apple Store) who has a MAc and see if their Mac recognizes the device. If so, copy that information onto a drive that your Mac does recognize. Then reformat the external drive and test on your Mac again.
Good luck,
SK
I’m new to Mac, so was a little confused with some instructions but tried the slow jam as it was a simple process and by golly it worked! Thanks a lot.
Thank you, Elizabeth, for writing up this list. I’ve been frustrated for months with my SanDisk USB 3 thumb drive not mounting after I ejected it or after the computer was put to sleep–and I had to resort to rebooting my MBP 2015 to mount it. But Slow Jam works overtime! Amazing!
Hi Paul,
Thanks for letting us know. We love the Slow Jam too! Always works on our Thumb Drives! Awesome! Love that easy things work…sometimes.
Liz
Thanks very much! It worked 🙂
Kext Utility worked for me… I went down your list one by one, finally got a winner at the end.
You’re a life saver. Thanks
It worked for mw thew first time, then i turned off my macbook pro 2019 with the touch bar model, turned on agaiun, and is not recognizing the external disk anymore, it mount it perfectly in disk utility, it displays like mounted, first aid sais its working fine, but i cannot see my disk in the desktop, i turned on and off the checkbox in finder preferences and reseted the NVRAM, also terminal stuff… nothing seems to work, not even the slow jam 🙁
Great article! Slow Jam worked for me.
This is great content! Thanks for the help with an external drive issue.
This is the Console error 🙁
AWDAgent: failed create new libnetcore metric for 0x290007
BTW, thanks for posting this.
I am seeing it in the terminal, but it will not let me “eject” it. It keeps timing out. :/
WD Mybook unrecognized by Powerbook OS 10.9.5, finally got error message that drive could not be accessed, and opened Disk Utility with error window still onscreen. Repair didn’t work, but I was able to Erase the 4 terabyte drive and the software recognized disc. Now backing up with Time Machine, seems to be functioning normally.
Tony,
That’s great. Thanks for sharing what you did that worked!
SK
The slow jam worked smoooothly. Thanks a lot! You saved me 60 bucks.
LMAO, never thought the slow jam would actually work xD