Trying to reinstall Big Sur after Monterey upgrade - "volume cannot be downgraded"
Hi community.
I installed Monterey earlier today on my 2020 M1 Macbook Pro, on the promise from the software provider that some of the software I'm using would be compatible. It's not. I had half expected that so made sure I had a valid Big Sur install disk and Time Machine backup before upgrading.
I've gone to install from my Big Sur install disk and when I select the install destination as Macintosh HD it tells me "The volume cannot be downgraded."
Alternatively I tried restoring from a Time Machine backup that I made just prior to installing Monterey, but that tells me I must use Migration Assistant or reinstall the OS (which I can't do because the volume cannot be downgraded). I was of the understanding that Migration Assistant was for transfering data between Macs, not restoring a backup.
What do I do?
How do I make the volume downgradable?
Help me community. You're my only hope.
MacBook Pro (2020 and later)