The macOS Big Sur update, while full of improvements, is not without its problems: users have encountered a variety of bugs, including problems that temporarily clogged their Macs, video sorting issues, sudden slowdowns, and more. Some users have preferred to fully revert to macOS Catalina and wait for all major bugs with Big Sur to be fixed.
If that describes you, there is a way to roll back Big Sur and get back to the more pleasant Catalina OS, although this requires the correct procedure. Here’s what to do.
Step 1: Backup your data
If you haven’t already, now is the time to back up your data. You can always use Time Machine to back up data on a Mac, but operating systems with errors can make Time Machine difficult to use, so it’s smart to find a backup method that doesn’t depend from macOS.
An external hard drive is very useful here. If you have a lot of iCloud space, you can also store all important files in iCloud for easy retrieval when needed. Oh, and if you’re using a MacBook, this is also a great time to plug your Mac into a power source and set it up where you can stay for a while.
Step 2: Exit and enter recovery mode
Close all your apps and shut down your Mac completely. You can press the physical power button or select and choose the Apple icon at the top left Shut down to start. It may take a while for your Mac to shut down completely. If a bug pops up and your Mac freezes during this process, press and hold the power button for a few seconds to force shutdown.
When your Mac is turned off, unplug all accessories except your mouse and keyboard. Then press the power button to turn it back on. When your Mac is starting up, immediately hold down the Order and R. buttons until you see the Apple logo appear. Now let go of those keys and your Mac should enter recovery mode. You will know this worked when you see the window with the name MacOS utilities to show up.
Note: If you have a Mac with an Apple silicon chip, pressing and holding the power button will take you to a boot menu, where you have to choose Options instead.
Step 3: Look for a Time Machine backup
To research MacOS utilities. The first option should be Recover from Time Machine Backup. Start by selecting and then choosing this option Continue, and your Mac searches for Time Machine copies of your operating system.
Here’s where things get a bit tricky: if you know you have a Time Machine copy and it’s stored on an external hard drive, you’ll need to plug in that external drive before choosing this option. If you’re not sure if you’ve set Time Machine to make regular copies, let your Mac search and see what it finds.
If your Mac returns a Time Machine backup, find out what operating system it is and the date it was created. You want a Time Machine backup from just before you installed Big Sur. If a copy looks the way you need it, select it and select a destination drive where the backup will be saved. Then select To recover, and choose Continue when requested. You may be asked to choose categories of information to restore. If so, choose them all.
Step 4: Use the Reinstall macOS option as an alternative
If you haven’t used Time Machine and don’t have backups, there is another option you can try. Go back to macOS Utilities and this time choose it Reinstall macOS option. Select Continueand enter your Apple ID. Your Mac will then search for an internet connection, which is necessary for the reinstallation. If your Mac is having trouble connecting to Wi-Fi, you may need to connect an Ethernet cable from your router to your Mac for a wired connection.
Important note: This process is effective if Big Sur has trouble booting after a buggy installation. If Big Sur is already installed and you’ve already used it, it might be reinstalled – which isn’t what we want. There are ways to get around this!
- Try rebooting in recovery mode first, this time with the Alt + Order + R. Keys. This should ensure that the Please install again option is set to the version of macOS your Mac came with. If you have a Mac that’s only a year old, it should be MacOS Catalina, which will solve your problem.
- If your only option is to reinstall Big Sur, you should instead create a bootable installer with macOS Catalina and use it as the boot disk. Apple has specific instructions for this process, which is not complicated, but requires a 12 GB flash drive.
When your Mac goes to reinstall MacOS Catalina, it will take an hour or two to finish, so stay patient. The good news is that your files and apps – unless they are corrupted – should be saved and ready after your Mac is done.
Step 5: Erase your startup disk if necessary
If you’ve tried everything but your Mac is still experiencing serious glitches that make it unusable, you should try to wipe the startup disk completely. Select Disk Utility at the MacOS utilities menu, select Continueand then choose your startup disk from the menu options. Not sure which disk it is? If your Mac is still working, you can go to System preference and select Boot disk take a look.
Select now To clear. Your Mac lets you choose which format to use – choose APFS. When prompted, choose partition GUID partition map. Confirm the process and the boot disk will be erased, allowing MacOS Catalina to be installed. Since many Mac setups use an extra drive to store personal files, these can be left largely intact.