Solution: For me, the issue has been caused by an incompatible plugin (MinimizeToTray).
Start Thunderbird in safe mode (thunderbird -safe-mode). If Thunderbird starts up and looks normal so far, the issue is likely caused by some of the extensions which are disabled in safe mode - the way outlined here will help you, otherwise you have a different problem from me. In safe mode, have a look at the installed plugins. For me, MinimizeToTray had already been marked incompatible with my release of Thunderbird. After removing the plugin and restarting, Thunderbird worked just fine, also in normal mode. I'm wondering why the plugin was able to cause havok even though Thunderbird knew it was malign (and should not have loaded it, just as in safe mode). Anyway: Issue solved for me. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/827509 Title: Thunderbird does not appear in Unity 2D messaging menu To manage notifications about this bug go to: https://bugs.launchpad.net/unity-2d/+bug/827509/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
