I looked through other similar issues on the support forum, but everyone's problem seems to have its own idiosyncracies ... I have 3 gmail-based accounts that run through Thunderbird 38.3.0 on my desktop -- all 3 are configured the same; the other 2 behave normally (their deleted messages go into a corresponding Trash folder in Thunderbird). On the problem account, however, my deleted messages appear in a Trash folder through 8/26/15, then nothing after -- which makes me think the problem is the result of a Thunderbird software update? I have not changed any settings ... Looking at the folder tree of each account, the only difference I see between the 3 accounts is that the 2 that are working correctly have a Gmail/Trash folder (with trashcan icon) where the deleted messages go; the problem account has only a Trash folder (with folder icon), where deleted messages stopped going after 8/26, but no Gmail/Trash folder (with trashcan icon). Again, I haven't changed any settings. Even more strangely, under Tools: Account Settings: Server Settings, all 3 accounts are set up the same way -- "When I delete a message, Move it to this folder: Trash (folder icon) on (email address)." This doesn't seem to make sense. Any help is welcome!