Time Machine fails with "unable to create a snapshot of the disk" after upgrading to Monterey.
After upgrading to Monterey, Time Machine backup fails. For TM, I'm using a USB-connected drive on my mac Mini with a 3T volume (APFS, case-sensitive) which is completely empty. I deleted all previous local snapshots in case that was part of the problem, but no luck. Within seconds of a backup attempt, I get a message "Time Machine could not back up the disk “Macintosh HD” because a snapshot of the disk could not be created.".
Any suggestions?