The last days we have encountered a situation where the upgrade to MacOS Monterey 12.1 or 12.2 fails.
After several reboots the machine returns to the state before the upgrade started, with the addition of several applications crashing upon startup and needing reinstalls of these. This has happened to several machines, both Intel and ARM models when trying to upgrade from various MacOS versions such as 12.0.1 and 11.6.x.
Several repeated attempts give the same result:
It occurred that we might have a compatibility issue with Defender ATP (101.56.35) - and after removing this application completely and retrying the OS upgrade, this was completed without any issues.
Defender ATP was then reinstalled and now works without issues. The same goes for other applications that were "corrupted" during the first tries. Among them are OneDrive and Teams. After a "delete and reinstall" they all now work fine.
A less "Brutal" approach is also tried out (edit: which did not help) disabling various Defender modules, but this is rather time consuming since we do not know the result before the whole upgrade process is "complete".
Anyone else seeing a similar pattern?
