Mac OS latest version. Had Thunderbird for many years. Suddenly it is locked up. has the normal screen for checking mail but there is a circle going round and round...trying to finish some process.. Progress thermometer on bottom is solid blue. Just does not clear up. All of to settings and they are the same. Can get into my address book. but can't pull up any new or old messages. Tried to remove program and re-install but it seems to keep some part and on re-install it goes back to the spinning circle of an unfinished process. Have tried to remove all parts and re=boot the OS..same thing comes right back I would give almost anything to get this e-mail program back up and running