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How can I downgrade from macOS Big Sur to macOS Catalina?

How can I downgrade my MacBook Pro from macOS Big Sur to macOS Catalina?

MacBook Pro 15″, macOS 10.16

Posted on Jul 8, 2020 11:20 AM

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Question marked as Apple recommended

by erasing your entire drive from recovery and then reinstalling the previous version from the backup you made before installing big sur.

Posted on Jul 8, 2020 4:32 PM

2 replies
Question marked as Helpful

Sep 1, 2020 10:02 AM in response to ZackaryScott

let's be real, who really makes a backup? probably not the kinda person who tries out a beta.


I do. I've been making bootable clone backups for at least 15 years. It is essential unless you have nothing valuable stored on yours. I do have important files and data.


I wouldn't be silly enough not to do a backup before installing a bug ridden beta which can render your device totally unresponsive/dead/nothing works - not even recovery. As well, you cannot restore an older OS with recovery unless you want the original OS installed.

78 replies
Question marked as Helpful

Sep 1, 2020 10:02 AM in response to ZackaryScott

let's be real, who really makes a backup? probably not the kinda person who tries out a beta.


I do. I've been making bootable clone backups for at least 15 years. It is essential unless you have nothing valuable stored on yours. I do have important files and data.


I wouldn't be silly enough not to do a backup before installing a bug ridden beta which can render your device totally unresponsive/dead/nothing works - not even recovery. As well, you cannot restore an older OS with recovery unless you want the original OS installed.

Sep 1, 2020 10:48 AM in response to ZackaryScott

ZackaryScott wrote:

let's be real, who really makes a backup? probably not the kinda person who tries out a beta.

You're kidding right? The question should be "who would instal a beta system on one's working boot drive without a backup of the drive, preferably a bootable clone backup"?


An experienced beta tester will clone their working drive to an external HD, boot from it and install and test the beta on it.

Sep 28, 2020 4:40 AM in response to aum18

I know the way of clean install of a previous version. For this, you need to follow these steps:

1. Make a backup copy of your Mac’s data

  • Go to System Preferences → Time Machine
  • Click on Select Backup Disk… → choose the disk and click on Use Disk.


2.Download macOS Catalina or another system you want to use instead of Big Sur

Basically you have several options for installing another Mac operating system:

  • Time Machine backup.
  • Internet Recovery.
  • Bootable installer.


3. Erase Macintosh HD

  • Restart your Mac in Recovery mode. For this, first shut down the computer. Then press and hold the Command (⌘) + R shortcut and at the same time press the power button.
  • You will see the macOS Utilities window. Select Disk Utility and click Continue.
  • You will be switched to the Disk Utility window. Here in the sidebar select Macintosh HD – Data volume and click to Delete APFS Volume from the context menu.
  • Then, in the sidebar select Macintosh HD and click to Erase. You will need to provide a name, choose a partition map and format.
  • Quit Disk Utility and restart your Mac.


4. Rewind macOS

Now you are ready to downgrade from macOS Big Sur to Catalina. As I mentioned above, you can restore the earlier macOS from the backup or reinstall it using a bootable installer.

If you use Time Machine, follow these steps:

  • Connect the external drive with a backup to your Mac.
  • Restart your Mac in Recovery Mode.
  • You will see the Utilities window. Select Restore From Time Machine Backup → click on Continue → confirm it.
  • Select your Backup Drive and click Continue → choose the desired backup version with macOS Catalina and click Continue → select your Macintosh HD (startup disk) and click to Restore.
  • When done, restart your computer in the usual mode.

source - https://nektony.com/how-to/downgrade-macos-big-sur

Nov 4, 2020 2:10 AM in response to Old Toad

I installed macOS Dev/Big Sur on Mac Pro late 2013 over a month ago and all along backed-up my computer to TimeMachine along with my original back-up of macOS Catalina.


With over a month's worth of work using macOS Big Sur, if I follow your directions, my restored macOS Catalina will not recognize my macOS Big Sur TimeMachine back-up's and I will lose everything I did while using macOS Big Sur.

Nov 4, 2020 11:09 AM in response to babowa

I enjoyed using macOS Dev/beta Big Sur until my printer stopped working with a warning "hpPostScriptPDE.plugin" will damage your computer.


And a Data volume appeared on my Desktop that mirrored my storage as another accessible volume, reducing my 1TB SSD to 16GB of available space, and Time Machine refused to run because it found two copies of the "Data" volume; I also found 25 unknown disks on my Terminal's diskutil list.


All in all, It was a good day to do a complete house cleaning and rebuild my computer from scratch.


The moral of this story is:

"Watch out for shiny objects."

How can I downgrade from macOS Big Sur to macOS Catalina?

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