Further to my previous comment, Thunderbird still is occasionally exiting on start-up. The problem goes away after starting it from the command line, switching to the calendar (Lightning) and then exiting, but this is not a permanent fix.
Further to my previous comment, Thunderbird still is occasionally exiting on start-up. The problem goes away after starting it from the command line, switching to the calendar (Lightning) and then exiting, but this is not a permanent fix.