Today received this error when checking my UW email with mbsync:

Error: channel uwoutlook, far side box Calendar: Unable to recover from UIDVALIDITY change.

I searched a bit for an easy solution and it seemed that the consensus was to delete your local email repository and resynchronize with the server. I’m just noting here that deleting the offending directory in your local email repository appeared to work. For example, above it is the “Calendar” directory under my “uwoutlook” mail directory (channel, in mbsync).

For me, that was a much smaller resynchronization job.

Debian linux

mbsync --version
isync 1.4.4

[mu4e] Found mu version 1.11.22