Originally Posted by
birdstrike
Since that time, it appears that even after I quit Thunderbird, my mail is still being read (for my original email address). I want to find and resolve that issue, not work around it.
Something else is holding open Thunderbird. Either the exe isn't actually terminating, an extension is remaining in memory or something else is happening, but it seems pretty clear that the client is remaining active in memory. Logging out your system will certainly make sure that the app terminates. Or you can log in with nothing else running and then see what other processes launch when Thunderbird starts to see if that helps you find some other app that is remaining in memory.
Are you running something like ThunderTray that puts in in the system notification area?