@simon I confirm you solution. Before upgrading from 9.04 to 9.10 i was using downloaded Thunderbird from Mozilla website, i.e was not installed from Ubuntu repositories. After upgrading to 9.10 i found that Thunderbird wasn't working at all. I just removed it and reinstalled it from Ubuntu repository "apt-get". I made a backup of my last Thunderbird profile and replaced it with the new profile "~/.mozilla-thunderbird/". Now here was the problem, the backed up profile already contained the previously installed extensions which were downloaded from Mozilla website. So as @simon said "You have to uninstall Lightning from within Thunderbird Addons then install from the repositories (using Synaptic if you want)."
-- [Karmic] Lost Lightning calendars when upgrading from 9.04 to 9.10 https://bugs.launchpad.net/bugs/476520 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
