Yesterday, 13/09/2023 Norton Software Updater said my Thunderbird client needed updating. I clicked to update, and it said it was sucessfull. Today I clicked on my Thunderbird shortcut and it could not find the file/s. Appears that Norton Updater had deleted my Thunderbird files!!!!!!
I contacted Chat and was advised to reinstall Thunderbird. When done it found my emails/folders. Phew...........
While I use the software updater to scan for new versions I never allow it to update. There are too many problems with allowing it to update as you have found with Thunderbird.
If it finds something I investigate it manually and then update thru the actual program itself or on the manufacturer's website. This is true for Norton Software Updater as well as any other updaters on the market especially driver updaters.