I had exactly the same problem. My solution was to check the alphanumeric foldername (xxxxxxxx.default) in the /home/username /.mozilla-thunderbird folder. I discovered I had appended the word "NEW" to the 8 character.default name during a file transfer from another computer. Once I removed "NEW" from the folder name, all returned to normal.
-- (Kubuntu Intrepid) Thunderbird says it's already running but isn't https://bugs.launchpad.net/bugs/273351 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs