OMFG do NOT lose control of the account that your macOS machine has Activation Lock tied to.
Kid’s 2016 MacBook Pro had some unrepairable disk errors and recurrent crashing. Went to Recovery Mode which accepted his _current_ AppleID to login to reformat the drive and recover from a backup.
But of course the Backup has the original Activation Lock and account. So for whatever reason it absolutely would not make it all the way through a boot up after a full restore.
Tried that a couple different ways and likely full borked the on-disk OS. Somehow got a 171GB “Update” partition that wouldn’t go away.
Along the way managed to get the machine removed from Find My in the current Apple account.
Then back to recovery mode, full erase and repartition disk. Recover over internet, install Sequoia from zero, and now using Migration Assistant from backup to bring everything back together.
Fingers crossed that by morning it’s all happy again.
I’m sure I fucked up somewhere early in the process…quite the adventure. At least we know someone who steals the machine would be S.O.L….