User-Agent: Mozilla/5.0 (X11; U; Linux i686; fr; rv:1.8.1.5) Gecko/20070727 Firefox/2.0.0.5 Build Identifier: 2.0.0.5 When thunderbird is closed while the hard disk containing the home directory (and so thunderbird user's storage) is full, this may cause a corruption in the data and then you may notice empty mailboxes when you start it again, even if the mails are still here on the hard disk. Thunderbird shouldn't loose such data when disk space is 0, it should just be unable to store new data, but here it is completely loosing some directories in both newsgroups and mails. I consider this as critical cause when you use POP and keep your mails only on your computer, you will then loose data which can be important for you. Reproducible: Sometimes Steps to Reproduce: 1.Get several news posts from several newsgroups and/or mails in several directories 2.Fulfill your hard disk so that it gets full 3.Quit and start again Thunderbird Actual Results: Some of the folders that were here before closing may have disappeared Expected Results: They should still be there This problem is quite old, I decided to make a bug report now but I experienced this problem on every thunderbird version I used

dupe of bug 239455 . The extra download in that bug is a result from 'leave mail on server' in combination with the corrupt mail store.