* start thunderbird in safe mode (thunderbird -safe-mode )
* don't tick any boxes in the window that comes (don't permanently reset anything)
* once thunderbird starts, go to Tools->Addons and disable "Messaging Menu and Unity Launcher integration 0.8"
* close thunderbird
* start it in normal mode
-> thunderbird works fine.
So I think the problem actually lies in this extension rather than unity. I'm not sure if the extension is bundled with thunderbird, unity or a separate package, but its a confirmed issue in 12.04.
Solved as per: https:/ /lists. ubuntu. com/archives/ ubuntu- mozillateam- bugs/2012- April/132383. html
* start thunderbird in safe mode (thunderbird -safe-mode )
* don't tick any boxes in the window that comes (don't permanently reset anything)
* once thunderbird starts, go to Tools->Addons and disable "Messaging Menu and Unity Launcher integration 0.8"
* close thunderbird
* start it in normal mode
-> thunderbird works fine.
So I think the problem actually lies in this extension rather than unity. I'm not sure if the extension is bundled with thunderbird, unity or a separate package, but its a confirmed issue in 12.04.