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Installing or updating macOS is a fairly simple process. But sometimes, you’ll get an error message that says ‘An Error Occurred While Preparing the Installation’ right before the installation starts. Then, the update process won’t start, and you have to use other methods to keep setting up.
To get into Safe Mode, restart your Mac while holding down the Shift key. If you have an Apple Silicon device, you need to turn off your Mac, turn it back on, and then keep pressing the Power button until the Startup Options appear on the screen.
Most of the time, your system will show this error message because the date and time settings are wrong or the installer build is not compatible. But this error can also be caused by corrupted NVRAM data and installation bugs and glitches.
(Fixed) ‘An Error Occurred While Preparing the Installation’ issue
Boot Into Safe Mode
- Turn off your Mac and then turn it back up.
- Immediately press and hold the ‘Shift’ button and keep holding it until you see the Apple logo. It’ll ask you to log in now. Log in with your credentials, you will have to log in several times.
- After that, your computer will enter ‘Safe Mode’. Try doing the installation now.
Use macOS Recovery
- Turn off your Mac.
- Turn on your Mac and immediately press one of the keyboard combinations:
- Command (⌘)-R: This reinstalls the latest macOS version that was installed on your Mac.
- Option-⌘-R: This will update your Mac to the latest compatible macOS version.
- Shift-Option-⌘-R: This will install the macOS version that came with your Mac.
- Click Reinstall macOS and then Continue.
Use a combo update
- Please note that you can use this method to update your Mac from a prior version of macOS within the same major release. For example, the macOS 10.15.4 combo update requires that macOS 10.15.0 or later is installed.
- Download the necessary macOS combo update from the Apple website.
- They are dmg files. Also, note that they are very large files.
- Double click the install the file. And then follow the onscreen instructions.
Change/Check Date and Time
When you want to upgrade macOS or install a new version, the installer tries to connect to the Apple servers. Servers check the date and time of a connection all the time. So, if the date and time settings on your MacBook are wrong, the installer will show an error message that something went wrong during the process.
- Open Apple Menu and select System Preferences.
- Go to the Date & Time option.
- Enable Set date and time automatically.
- Make sure your region is correctly chosen.
- Restart your Mac and try installing/upgrading the macOS to check if the problem has been solved or not.
Reinstall the OS Without Erasing the Drive
- Turn off and on your Mac and press and hold Command (⌘) + R.
- Release the keys to boot into Safe Mode and open the Utility menu.
- Select Disk Utility and click Continue.
- Select the disk, which is Macintosh HD for most users.
- Click on the First Aid option.
- Wait for a couple of minutes until the Done button activates. Click on it.
- Exit Disk Utility, go back to Utility Menu, and select Reinstall OS.
FAQ
Why error occurred when downloading macOS Monterey?
Most of the time, you won’t be able to download macOS if your Mac doesn’t have enough storage space. Open the Apple menu and click on “About This Mac” to make sure. Select “Storage,” and then make sure your hard drive has enough space.
Why does my Mac say an error occurred while downloading the updates?
System errors can sometimes be to blame for the Mac update error 102. Just restarting your Mac will refresh the operating system and get rid of any temporary bugs. Then, see if the software or system can be updated normally.
Why do my downloads keep failing on Mac?
Sometimes a file gets damaged and a download doesn’t finish. Try downloading it again. Make sure you have the app you need to open the file. If you do, it’s possible that the file got messed up while you were downloading it.
Why is my app not installing on Mac?
After trying to open a new app, go to System Preferences > Security & Privacy to let it. By updating macOS and restarting your Mac, you can fix a wide range of problems. Remove the app from your Mac and then reinstall it. System Preferences > Security & Privacy is where you can temporarily turn off your firewall. Aug 13, 2019