Hello there, checkout this link and I hope this will be of use to you www.makeuseof.com/tag/how-to-recover-deleted-emails-in-thunderbird/

Cheers

The folder was not deleted...it just disappeared with a dozen subfolders & c. 1000 messages. The messages are still around--a search finds them but doesn't tell me where they are. None of the tips for deleted folders or messages seems to apply to this situation.

If I "reinstall" my profile, will this overwrite all the more recent messages?