Comment by alister

A warning about Thunderbird: It sometimes deletes the entire email rather than just the attachment. It happens with both IMAP and with mail on your local disk. I'm on Linux with a vanilla install with no add-ons or extensions and I've seen this bug in recent versions and going back 5-7 years. There's at least one bug report filed and I think I also filed a bug report. Maybe it has something to do with my configuration because I would've thought many people would have seen it by now. I avoid deleting attachments unless I think the email itself is unimportant and don't care if it also gets deleted.