System freeze on first boot of the day after OS update 12.6.7 - any solutions? Mac Pro 2019.
Mac Pro 7.1, 12-core. Worked fine with 12.6.6 but after 12.6.7 I get a complete system freeze within the first few minutes of first boot. If I leave it to see it it will get over whatever issue it eventually shuts off without any dialogue. The CPU clearly gets VERY hot - it smells - and on re-boot the fans take off like a jet engine. It may then start normally, or need a second go. After that - all seems fine, until the next day...
I've tried re-installing the OS from recovery, having checked all disks with Disk Utility. Also tried resetting PRAM and starting into 'Safe' mode - no difference. The power to the studio is off overnight, so it gets an SMD reset daily. The latest Safari update is also installed.
I'd like to go back to 12.6.6, but in trying to re-install the OS, my CCC backup ended up getting the new installation, so I don't have a 12.6.6 backup as such. I have a 12.6.5 USB installer, but can't face having to re-install all my software plugins if Migration Assistant refuses to import from the 12.6.7 backup.
Any solutions or means to re-install 12.6.5 WITHOUT wiping the Mac SSD would be most welcome.
I do have a Catalina partition on the Mac SSD, which I could update to 12.6.5, but it would also involve a LOT of updating of plugins... Not a nice option.
Thanks in advance.
WH Mac Pro