After months of waiting, macOS Big Sur was released in November 2020. No matter how great macOS Big Sur is, you can experience performance issues as you update your Mac. The good thing is you can downgrade to the previous macOS version.
There are two ways to revert from Big Sur to Catalina. The first one involves restoring a Time Machine backup. The second, which is a bit lengthy, explains how to downgrade to Catalina using a bootable installer. Whichever way you choose, we'll provide step-by-step instructions to help you downgrade.
Open this article on your phone to make sure you do everything step-by-step.
Unless you’re planning to use the Mac’s Internet Recovery options to reinstall the original version of the Mac OS that shipped with your Mac, or you’re planning on restoring from a Time Machine backup or a clone you made before you upgraded to macOS Catalina, you’re going to need a bootable version of the Mac OS you wish to install. Close all open apps. The Catalina installer can be run directly from your current Mac startup drive when you perform a clean install on a non-startup drive. Launch the macOS Catalina installer app located in the /Applications folder. It will have a name similar to: Install macOS Catalina. The installer will open. Primary Steps to Wiping a Macintosh Hard Drive Running Catalina. These are the main steps to wiping your data from the computer. First you’ll be removing your Apple ID, then wiping security settings like your fingerprint ID. Then you’ll erase the drive and reinstall macOS. The entire process takes 1-2 hours. To perform a clean re-install in Catalina, once in Recovery Mode, you need to delete your Data volume, that’s the one named Macintosh HD - Data, or something similar if you’re using a custom name, and to erase your System volume. In Recovery Mode select the Macintosh HD - Data volume at the left of Disk Utility’s window then use the.
If you’ve backed up your Mac with Time Machine before upgrading to Big Sur, downgrading to Catalina will be easy. Here’s how to downgrade from macOS Big Sur to Catalina using Time Machine.
First, back up everything. Your Mac probably contains your personal data and documents that you don’t want to lose. So, to keep those alive after the downgrade, you need to back up your data.
You can use Google Drive, iCloud Drive, or any other cloud you prefer. After the backup is done, you can move on to the next step.
Before you begin reverting your Mac to macOS Catalina, it’s worth trying fixing performance issues on macOS Big Sur. Maybe you won’t need to downgrade at all.
CleanMyMac X can help identify and solve performance problems on your Mac. It’s a dedicated Mac cleaner that clears old junk and runs optimization tasks. It’s notarized by Apple, which means it’s safe for your Mac. Get CleanMyMac X for free to run a quick performance scan.The first step is plugging your Mac into power (the downgrade process may take a while, and you don’t want your Mac to power off unexpectedly).
You’ll need to erase your Mac’s drive. This will remove everything from your Mac, but you can restore your data later from a Time Machine backup.
Wait for the process to complete. Only after every piece of data is removed, can you clean install macOS Catalina.
You can now restore all your files and data and bring your Mac back to the condition it was in before you installed macOS Big Sur.
If your Time Machine backup is stored on the external drive, plug it in your Mac.
So, to restore your Time Machine Catalina backup:
The process may take some time. Your Mac will restart running macOS Catalina.
If you didn’t back up your Mac with the Time Machine, it’s too bad. But, you can still downgrade to the previous OS version. Just follow the instructions.
Backing up your data is important. It prevents you from losing all the files and data that have existed on your Mac's drive for a while. So, don’t forget to back up your Mac before you start downgrading to Catalina.
A bootable installer will help you safely roll back to Catalina. Here’s how to create a bootable installer:
Now, it’s time to transfer your Catalina installer to your hard drive:
sudo /Applications/Install macOS Catalina.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume
The downloaded file, which is your bootable Catalina installer, should be in your Applications folder. MyVolume is the name of the hard drive; if your hard drive or flash drive has a different name, replace MyVolume with the name of your hard drive.
Quit Terminal and eject the hard drive.
Now, you can roll back from macOS Big Sur using the bootable installer.
Your Mac will then start installing macOS Catalina and will restart when it’s done.
If your Mac is slow after the update, but you don’t want to perform this lengthy process and revert to the previous OS, you could try a quick solution. CleanMyMac X has a helpful Maintenance feature that could fix all possible problems on your Mac.
Wait till CleanMyMac X runs the set of fixes to speed up your Mac.
Reverting to the previous macOS may seem like a terrifying task. But if you open this article on your phone or another device and follow the instructions, it will be much easier and faster. Don’t forget to clear your Mac before the backup – you will save a lot of free space and remove old clutter that slows down your machine.
These advanced steps are primarily for system administrators and others who are familiar with the command line. You don't need a bootable installer to upgrade macOS or reinstall macOS, but it can be useful when you want to install on multiple computers without downloading the installer each time.
MyVolume
in these commands with the name of your volume.Big Sur:*
Catalina:*
Mojave:*
High Sierra:*
El Capitan:
* If your Mac is using macOS Sierra or earlier, include the --applicationpath
argument and installer path, similar to the way this is done in the command for El Capitan.
After typing the command:
Y
to confirm that you want to erase the volume, then press Return. Terminal shows the progress as the volume is erased.Determine whether you're using a Mac with Apple silicon, then follow the appropriate steps:
A bootable installer doesn't download macOS from the internet, but it does require an internet connection to get firmware and other information specific to the Mac model.
For information about the createinstallmedia
command and the arguments you can use with it, make sure that the macOS installer is in your Applications folder, then enter the appropriate path in Terminal: