How to install macOS or OS X on a new hard drive for your Mac

There are several reasons you might need to install a new copy of macOS or OS X on the hard drive in your Mac or MacBook. Fortunately, there are also several ways to do it, ranging from Internet recovery to installation discs. 

In this article, we’ve given detailed instructions for each method.

So, it doesn’t matter if you want a clean slate on a second-hand MacBook or if you replaced the drive in your age-old machine, we’ve got you covered. Simply follow the instructions below to install the latest compatible version of macOS or OS X on your new hard drive.

Quick Tips

If you’re tech-savvy but don’t know where to start, use these Quick Tips to point you in the right direction for getting macOS or OS X on your drive:

1. Install macOS or OS X from Internet Recovery Mode, which you can boot into by holding option+command+R while your Mac powers up.
2. Download the relevant macOS or OS X installer from Apple, then use Terminal to create a USB installer you can boot up from.
3. Or use the OS X installation disc that came with your machine — or buy a new one — to boot up and install OS X on your Mac’s hard drive.

Related:

• How to downgrade from macOS Mojave to macOS High Sierra
• Factory reset MacBook Air and other Macs with macOS
• How to create a macOS Catalina USB installer
• macOS could not be installed, how-to fix

Format your new hard drive for macOS or OS X

You may need to reformat your new hard drive before installing macOS or OS X on it. This erases everything on the drive. If you don’t want to lose data from your hard drive, export the data or back it up before continuing.

It’s easy to reformat your hard drive using Disk Utility in macOS or OS X. If your Mac doesn’t work, you can do this using a second Mac and an external hard drive caddy. Otherwise, you can skip this step and do it from the Utilities page during the macOS or OS X installation.

How do I use Disk Utility to reformat my hard drive?

1. Open Disk Utility.
2. Select your new hard drive from the sidebar. If you don’t see it, go to View > Show All Devices.
3. Click the Erase button at the top of the window.
4. Choose a new name for your Mac’s hard drive.
5. Change the format to Mac OS Extended (Journaled).
6. Click Erase.
7. When the process is complete, press command+Q to close Disk Utility.

   

Install macOS using Internet Recovery Mode

The simplest way to install macOS or OS X on a new hard drive is by using Internet Recovery Mode. This mode is only available on Apple computers made after 2009 that were running OS X Lion or later.

If your Mac is from before 2009 or never had OS X Lion, click here to jump to the next section.

Internet Recovery Mode downloads the latest compatible version of macOS or OS X over the Internet and installs it to your hard drive. The entire process may take several hours depending on the quality of your Internet connection.

How do I use Internet Recovery Mode to install macOS or OS X on my hard drive?

1. Power off your Mac from the  menu or by holding the power button.
2. Briefly press the power button, then immediately hold the command+option+R keys while your Mac boots up.
3. Release the keys when a spinning globe appears onscreen.
4. Connect your Mac to the Internet by choosing a Wi-Fi network.
5. After a short while, the macOS Utilities window should appear.
6. If you haven’t done so already, follow these instructions to format your hard drive to work with macOS or OS X.
7. Click ‘Install’ and select your hard drive as the destination.
8. Your Mac downloads the latest compatible version of macOS or OS X over the Internet and installs it on your hard drive. It may take some time.

   

Create a bootable USB installer for macOS or OS X

If you can’t use Internet Recovery Mode, you can create a bootable USB installer instead. This is a USB flash drive with a specific macOS or OS X installer on it. You can boot your Mac from the USB flash drive to install the software on your Mac’s hard drive,

To create a bootable USB installer, you need a working Mac and you need to be comfortable using simple Terminal commands. If your Mac doesn’t work, try to borrow one or book an appointment at your nearest Apple Store.

You also need a USB flash drive with at least 12 GB of storage.

If you can’t create a bootable USB installer, click here to find out how to use a Mac OS X installation disc.

Which version of macOS or OS X should I create an installer for?

Our advice is to install the latest version of macOS or OS X that is compatible with your machine. This gives you the best security against malware and allows you to enjoy the latest available features.

But also, despite the fact that Apple’s latest software releases are free, you still need to pay for older versions of OS X. So if you don’t install the latest compatible version first, you might end up needing to pay twice!

If you already own an OS X Installation Disc, the simplest route is to install that and then update your Mac to the latest software. Click here to learn how to install OS X from your disc.

What versions of macOS or OS X are compatible with my Mac?

To find out the latest compatible version of macOS or OS X, you first need to know what model Mac you have. If your Mac turns on, go to  > About This Mac. Find your Mac model listed toward the top of the window.

Otherwise, find the serial number printed on the bottom or on the back of your Mac. It’s usually alongside other regulatory information. Enter your serial number into the Check Coverage page on Apple’s website. Find your Mac model listed at the top of the page.

Now, use the links below to look at the Hardware Requirements for each release of macOS or OS X. Start at the top of the list — with the newest release — and work back until you find your latest compatible software.

• macOS Catalina
• macOS Mojave
• macOS High Sierra
• macOS Sierra
• OS X El Capitan
• OS X Yosemite
• OS X Mavericks
• OS X Mountain Lion
• OS X Lion
• OS X Snow Leopard

If your Mac is only compatible with OS X Yosemite or earlier, you need to use an installation disc to get earlier software on your hard drive. Click here to find out how to do that.

How do I create a bootable USB Installer?

1. Use the links below or search the App Store to download the installer for your chosen version of macOS or OS X:
   1. macOS Catalina
   2. macOS Mojave
   3. macOS High Sierra
   4. macOS Sierra
   5. OS X El Capitan
2. After downloading, if the installer opens automatically, press command+Q to close it.
3. Connect your USB flash drive to the computer.
4. Open Terminal from the Utilities folder in your Applications.
5. Type sudo  into Terminal, including the whitespace at the end.
6. Open Finder and go to the ‘Install macOS’ app in your Applications folder.
   1. Control-click the app and select ‘Show Package Contents.’
   2. Open the ‘Contents’ folder, then open ‘Resources.’
   3. Look for a file called ‘createmediainstaller’ in the Resources folder.
   4. Drag and drop the ‘createmediainstaller’ file into your Terminal window. It should add the filepath automatically.
7. In Terminal, type --volume  including the whitespace again.
8. From Finder, select your USB drive, then drag and drop it into Terminal.
   1. If you can’t find it, from the menu bar select Go > Go to Folder.
   2. Type /Volumes/ and click Go.
   3. Now drag and drop your USB drive into Terminal.
      
9. In Terminal, press return.
10. Enter your administrator password then press return again. Terminal doesn’t show anything as you type the password, so make sure you enter it correctly.
11. Press Y to confirm you want to erase the USB flash drive.
12. Terminal shows its progress as it erases and installs macOS or OS X on your USB flash drive.

How do I use a bootable USB installer to install macOS or OS X?

1. Connect the bootable USB installer to your target Mac.
2. Power off your Mac from the  menu or by holding the power button.
3. Briefly press the power button, then immediately hold the option key while your Mac boots up.
4. Release the key when a startup disk selection screen appears.
5. Choose to boot up from your USB installer.
6. After a short while, the macOS Utilities window should appear.
7. If you haven’t done so already, follow these instructions to format your hard drive to work with macOS or OS X.
8. Click ‘Install macOS’ and select your hard drive as the destination.
9. Your Mac installs macOS or OS X from the USB installer. It may take some time.

   

Use a Mac OS X installation Disc

If you’re unable to use Internet Recovery Mode or create a bootable USB installer, you can still use a Mac OS X installation disc. These discs are available for OS X Snow Leopard, OS X Lion, and OS X Mountain Lion. 

If your Mac is from 2012 or earlier, there was an installation disc in the original box. If you don’t have it, you can still buy OS X installation discs from Apple:

• OS X Mountain Lion
• OS X Lion
• OS X Snow Leopard

How do I install OS X on my hard drive using an installation disc?

1. If you have a built-in disc drive, power on your Mac so you can insert the OS X installation disc into the slot.
2. Now power off your Mac from the  menu or by holding the power button.
3. Briefly press the power button, then immediately hold the option key while your Mac boots up.
4. Keep holding option until a disc appears on the startup selection screen. If your disc never appears, repeat these steps holding the C key instead.
5. Choose to boot up from your OS X installation disc.
6. After a short while, the macOS Utilities window should appear.
7. If you haven’t done so already, follow these instructions to format your hard drive to work with macOS or OS X. 
8. Click ‘Install OS X’ and select your hard drive as the destination.
9. Your Mac installs OS X from the installation disc. It may take some time.

Contact Apple Support

If you’re struggling to install macOS or OS X on your new hard drive, you may be able to get one-to-one support directly from Apple. Visit the Get Support website to speak to an advisor online or make an appointment at your nearest Apple Store to see a Genius.

Generally speaking, Apple doesn’t charge anything for software repairs. However, Apple may be unable to offer service if they find out you replaced the hard drive in your Mac yourself, since this violates the terms of use. Apple may also be unable to help if your Mac is vintage or obsolete.

Let us know your experience in the comments below. If you’re still struggling to install macOS or OS X on the blank new hard drive in your Mac, we might be able to help you out!

Dan Helyer( Senior Writer )

Dan writes tutorials and troubleshooting guides to help people make the most of their technology. Before becoming a writer, he earned a BSc in Sound Technology, supervised repairs at an Apple Store, and even taught English in China.