Comment 8 for bug 258849

I prefer that you file the bug using apport this way there is no mistake if it is the same. Apport will mark it as a duplicate if it is. If you choose not to use apport follow the instructions and file a new bug report with the info and backtrace.
Here is a link to obtain a backtrace

https://wiki.ubuntu.com/MozillaTeam/Bugs

I have not set up page for anything but Firefox at this time but once i get time i will update it. Please follow the instructions on this link except replace firefox with thunderbird. You might need other debugging packages please obtain these by: once you add the ddeb repos and update search for thunderbird and install the dbgsym packages that relate to xulrunner or thunderbird. Please let us know if you need a hand.

First pace to start is using a new profile and disabling any and all extenions before trying to obtain a backtrace.