Yes, by "crashes" I do mean quits unexpectedly with the appropriate message and offer to report, restart, etc. I have been watching more carefully and it seems that messages with attachments cause this, but not all messages with attachments. Yes, if a message causes a crash and I restart mail, when I go to that message it will again cause a crash. I can get rid of the message by clicking on the next message and then shift clicking on the offending message. That will allow me to delete both. I can't wait for snow leopard.