All of a sudden and for no apparent reason last week, I started getting repeated crashes on OS X Mail with the polite but unhelpful message above. Nothing much out of the ordinary had preceded this sequence of crashes other than the odd force-quit out of Mail, having failed to quit gracefully by itself. Anyhow, it was completely unusable and a pain in the neck. A trip to crash reporter left me none the wiser: I don’t understand any of that stuff. I did all the other usual stuff like Repair Permissions and running Onxy etc, but non of it made any difference, I should also point out that I’ve a reasonably good backup habit.
I experimented by opening the Guest Account and using MobileMe’s Sync pane to import the four accounts I use on a regular basis (all IMAP) and seeing if that was OK. It was, it didn’t crash, it was stable & all the stuff loitering in my inboxes was still there thankfully! The fact that Mail worked fine in the Guest Account suggested to me that the problem I was having was not at a System level but at a User level.
Moving back over to my main User Account, I started reading round the web and I found an entry on neildixon.com suggesting that he’d had a few problems with corrupt mailboxes. I deleted ~/Library/Preferences/com.apple.mail.plist and try relaunching Mail and once it did, I then deleted almost all the smart mailboxes and rebuilt the four IMAP accounts.
So far this has been successful for me although it’s a pain that I have to remake the smart mailbox rules. Oh well!
In conclusion, in Mail starts unexpectedly quitting on you, you could try the following:
1. Delete ~/Library/Preferences/com.apple.mail.plist
2. Relaunch Mail and delete the smart mailboxes
3. Reimport or rebuild your accounts