Fix: An Error Occurred While Preparing macOS Installation

When you try to reinstall macOS, the following error message may sometimes pop on the screen: “An error occurred while preparing the installation. Try running this application again”. If you retry the installation, the error returns. Restarting your MacBook doesn’t help either. Follow the troubleshooting steps below to fix the problem. But first, don’t forget to back up your data before pursuing the solutions below.

How to Fix “An Error Occurred While Preparing the Installation” on Mac

Boot Into Safe Mode

Restart your Mac with the Shift key pressed to boot into Safe Mode. If you own an Apple Silicon device, you need to shut down your Mac, turn it on, and then continue to press the Power button until the Startup Options appear on the screen. Check for updates while in Safe Mode. If the error persists, restart your device two or three times in a row and try again.

Check Date and Time Settings

Additionally, check your date and time settings. Let your Mac set up the date and time settings automatically. Go to System Preferences, click Date and Time, and set the date and time zone automatically. Restart your Mac, and try to reinstall the OS.

If you can’t boot up your Mac properly, use macOS Utilities and Terminal to edit your date and time settings.

1. Shut down your Mac.
2. Then turn it on, and immediately press and hold the Command, and R keys to enter Recovery Mode.
3. Release the keys when you see the Apple logo on the screen.
4. Click on Utilities, and then select Terminal.
5. Run the ntpdate -u time.apple.com command to set the date and time automatically. If this command doesn’t work, try running sntp -sS time.apple.com.
6. If you’re offline, edit the settings manually using the date [mm][dd][HH][MM][yyyy] format. There are no spaces between [mm][dd][HH][MM][yyyy].

Reinstall the OS Without Erasing the Drive

1. Restart your MacBook, and press and hold the Command and R keys right after you hear the chime.
2. Release the keys when the Utility menu appears on the screen.
3. Select Disk Utility and click on Continue.
4. Select your disk. For most users, it’s Macintosh HD.
5. Then, click on the First Aid option.
6. You may need to wait for a few seconds, or a couple of minutes until the Done button becomes clickable. Hit Done.
7. Exit Disk Utility, go back to the Utility Menu, and select Reinstall OS X.

If reinstalling the OS won’t work, try erasing the drive first.

Erase the Drive Before Reinstalling the OS

1. Restart your Mac, and press and hold the Command, Option, and R keys right after the chime.
2. Release the keys when the globe or Apple logo appears on the screen.
3. Wait between 5 to 10 minutes until the Utility menu appears on the screen.
4. Then select Disk Utility and hit Continue.
5. Select your drive and then click on the Erase tab.
6. In the new panel, set the partition scheme to GUID, and select the format type to Mac OS Extended (Journaled).
7. Click on Apply and Done, and then quit Disk Utility.
8. Go back to the Utility menu, and select Reinstall OS X.

Recreate Your Fusion Drive and Add a New Volume on It

Use this solution only if your macOS device is equipped with a Fusion Drive. As its name suggests, a Fusion Drive consists of two different drives fused together. This is usually a combination of a Serial ATA drive (HDD) and an SSD.

First, erase the disk with Disk Utility and reformat it using the macOS Extended (Journaled) option. Then, follow the steps below.

1. Use the Utility menu and launch Terminal.
2. Check your drive Unix names by running the #> diskutil list internal command.
3. It’s important to note which is the HDD, and which is the SSD. For most users, the HDD is disk 1, and the SSD is disk0.
4. Now, run the #> diskutil unmount force disk2s1 command to force-unmount the logical volume.
5. Reformat your drives by running the following commands:
   • #> diskutil eraseDisk JHFS+ SSD disk0
   • #> diskutil eraseDisk JHFS+ HDD disk1
6. After that, recreate the disk with the help of the #> diskutil cs create “Macintosh HD” disk0 disk1 command.
7. Then, create a logical volume on the disk with this command:
   diskutil cs createVolume “Macintosh HD” JHFS+ “Macintosh HD” 100%
8. Exit Terminal and try to reinstall macOS.

Take Your Mac to Apple for Repair

If you’re still getting the same error even after erasing the drive, this may indicate your disk is faulty. If your machine is equipped with an HDD, you need to replace it. If your Mac has an SDD, take it to Apple for repair.

Conclusion

If your MacBook says that an error occurred while preparing the installation, boot into Safe Mode and check your date and time settings. Then, boot into Recovery Mode, run First Aid and try to reinstall the OS without erasing the drive. If the issue persists, erase the drive and try to reinstall the OS. Did you manage to fix the problem? Let us know in the comments below.