Ack! Stupid AD - Office 365 sync issues again.
This user has an in-place archive and there's an issue sycing its ID from Office 365 with that from AD... except that value just doesn't exist in AD.
It should be msExchArchiveGUID, but it ain't there.
Deleting that archive isn't even possible either, as it won't let me change it in o365 due to the sync an again locally it doesn't exist at all.
Update on the Longbow.
Time to do some work.
Almost, but not quite, shoot.
Tell me more about this internet.