You can downgrade from the macOS Big Sur beta to macOS Mojave to go back to a stable version of macOS and avoid any macOS Big Sur beta problems. This is relatively easy to do, but it does take a little time to complete. Right now this will move you off the developer macOS Big Sur beta, but the same process works for the public beta later this year.
If you prepared for the macOS Big Sur beta, this is an easy process since you have a good Time Machine backup handy. Plan on spending at least 30 minutes working on this and longer waiting on it.
The easiest way to downgrade from the macOS Big Sur beta to macOS Catalina is to restore a Time Machine backup that you made on Catalina. This puts you right back to where you were before you switched. You’ll need to manually back up any files or photos that you’ve created since the switch.
Here’s how to downgrade from the macOS 11 beta and go back to macOS Catalina.
How to Downgrade the macOS Big Sur Beta to Catalina
Plug your Mac into power if it is a laptop as this will take a while and it is a power intense task. You don’t want your Mac to power off halfway through this process.
Downgrading is a multi-step process that erases your Mac, installs the lastest version of macOS Catalina and then you will restore from a Time Machine backup. It takes a little time, but it is easy to do.
You need an Internet connection and this process is aimed at users who installed the macOS Big Sur beta on their main drive.
Erase Your Mac Drive
- Restart your Mac using the Apple menu in the upper right.
- When it is restarting hold Command and R until the Utilities menu appears.
- Choose Disk Utility
- Click Continue and then Click on Startup Disk. Often labeled Macintosh HD
- Click Erase.
- Choose the APFS file format from the list and click on Erase.
The macOS Catalina operating system uses APFS, so you won’t need to mess with the Mac OS Extended system that you may have used in previous versions of macOS.
Reinstall macOS Catalina
It takes a few minutes to erase the drive. Wait for this process to finish even if it seems like it is stuck or frozen. Once completed, you can start installing macOS Catalina.
- On the main macOS Utilities screen, choose Reinstall macOS.
- Click Continue and then Agree to any terms and conditions.
Wait for the Mac to restart and then you are back on macOS Catalina.
Restore Your Time Machine Backup from Catalina
Once you are back on macOS Catalina, you can restore your backup to put all your files and programs in place. The Time Machine backup that you made before installing the macOS Big Sur beta contains all this information on it.
If you want, you can skip this step and start fresh, which may be smart if you were having macOS Catalina problems.
- Restart your Mac and hold Command and R to get to macOS Utilities.
- Choose the Restore From Time Machine Backup option.
- Click Continue. Then choose the backup that you want to restore from. You will need to connect to WiFi if you have a wireless Time Machine drive or plug in if it is on an external drive.
- Click Continue after you choose the latest backup and then wait for the restore to complete.
The Time Machine restore process will take some time to finish. The best thing you can do is step away and check in on your Mac every 30 to 60 minutes to see if it is done.
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