Want to downgrade from macOS Big Sur to Catalina? In this guide, you’ll find essential steps you should follow to ensure you don’t lose your data.
Although macOS Big Sur comes with a lot of useful enhancements and a nice redesign, there are always computer users who may decide they would really like to roll back to earlier macOS. If you have recently installed Big Sur but for some reasons want to go back to Catalina, read this short guide to learn what you need to do to perform this process safely.
Back Up Your Mac
The downgrade process will completely erase your hard drive, and all your files, photos, music, videos, and other important data will be gone. That’s why before you proceed, you should back up everything that is stored on your Mac so you don’t lose your precious files. You can use an external drive, or sync them to iCloud Drive, Google Drive, or other cloud-based storage.
Downgrade via Time Machine
Restoring from the earlier Time Machine backup is the easiest way to downgrade. So if you have backed your Mac before installing Big Sur, follow these steps.
Erase Your Mac’s Hard Drive
- First of all, you need to plug your Mac into power and restart it (click on the Apple menu and choose Restart).
- As your Mac starts rebooting, you need to press and hold the Command and R keys.
- When you see the Utilities menu, select the Disk Utility option.
- Then click Continue and choose Startup Disk.
- Now click on the Erase tab and choose the APFS file format from a dropdown menu.
- After that, choose GUID Partition Map, and finally press Confirm.
After the process is complete, you can reinstall Catalina.
Use Time Machine to Restore Catalina
Now you can recover the earlier version of macOS. Here is what you should do.
- Restart your Mac again, and when it reboots, hold Command-R.
- Now, choose the option Restore From Time Machine Backup and after that, click Continue.
- In the next window, choose your Time Machine backup disk.
- After that, you need to choose the backup you would like to restore from. Click on the most recent backup that you made before upgrading to macOS Big Sur.
- Choose the destination disk where you want to store the contents of your backup. Finally, press Restore and then, click Continue.
The whole process is rather time-consuming, so you’ll have to wait patiently. When it’s complete, your Mac will automatically restart and will be running Catalina.
Downgrade Using a Bootable Installer
If you don’t have any Time Machine backups, there’s still another option you can try to downgrade to the previous macOS version. You just can do it using a bootable installer. You should start with backing up your recent data or perform a full data backup if you haven’t done it earlier.
First, you need to create a bootable installer. So plug in an external drive with no less than 12 GB of free storage. Then go to the App Store and download macOS Catalina. After that, open Disk Utility and erase your hard drive, choosing the Extended format.
When the process is finished, transfer the Catalina installer to your hard drive and use it to reinstall the Catalina OS. Replug your hard drive (it’s your bootable installer) and open System Preferences. Then choose Startup Disk, select the bootable installer, and press the Restart button. Your Mac will restart in the Recovery mode. Make sure it is connected to WiFi because the process will require the Internet connection. Now select Install macOs in the Utilities. Click Continue and follow the further instructions on the screen.
When the reinstallation process is done, the Mac will restart automatically and will be running macOS Catalina.