downgrade from Big Sur to Catalina
I've tried to follow instructions to downgrade my macOS. When I go to reinstall, the only option it gives me is to reinstall macOS Big Sur. How can I get back to Catalina?
Mac mini 2018 or later
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Revert your Mac to a previous macOS version
Other option and understand - the below option will Destroy ALL DATA on the drive. There are No Do Overs - period.
USB Installation & Wipe and Install
To perform this action will require booting from a Bootable Installer. This will have to be performed from a Qualifying Computer to run the version of macOS to be made on the Bootable Installer. Example : Bootable Installer of Big Sur would have to be done on a computer that Qualifies to run Big Sur.
Once that is done read on for preparing the Destination computer >> Special Notation - works on Intel Based Apple Computers & May on Apple Silicon M1 CPU
Extra Special Notation regarding the Touch ID / T2 Chip equipped Apple Computer. About Startup Security Utility and Must Enable from Recovery Mode the ability to boot from External Drive Before Attempting
1 - Shutdown computer and disconnect all external drive Except the newly created Bootable Installer.
2- Restart and immediately hold the OPTION key until the Startup Manager appears and choose the USB Drive.
3 - It will present options >> Disk Utilities >> View >> View ALL attached Drives.
4 - Choose the Upper Most Drive ( not the volumes indented and list below ).
5 - The drive normally is called Apple Media or Apple SSD - that is the drive to Erase and format as APFS with the GUID Partition Map.
6 - Once that is done >> backup out of Disk Utilities and choose install macOS.
7 - Follow the prompts and it may automatically reboot several time.
8 - Upon a final reboot - Setup Assist will present with the newer version of macOS.