Additional notes in as I'm having similar problems: I noticed problems with Thunderbird starting on May 24, 2022, but I also had installed addon Owl for Exchange and so I assumed the Thunderbird issues were caused by the new addon, which didn't make sense because of some of the problems: 1. Archiving messages not working (except when first opening Thunderbird with one or two messages!?!) with either the "Archive" button or keyboard shortcut. I can still move messages out of the inbox by dragging them to folders. 2. Message drafts not saving. 3. As the original post by zuberstan51 noted, Thunderbird is sometimes taking unusually long to perform operations. Right now I thing it just crashed.... (I'm running Thunderbird on an Ubuntu variant (Pop!_OS 22.04 LTS).) Thank you for any suggestions!