Whenever I close Mail and re-open it, all the settings revert back to how they used to be since before upgrading to Lion (I'm on 10.7.3). I used to have Gmail and an IMAP account for school, and there were several old SMTP servers still in the list. I've since gotten rid of the IMAP and added an Exchange account, and deleted all the old SMTP servers from the list. Yet each time I close Mail and re-open it, it reverts back to all the old accounts! This is maddening! Any ideas how to fix this? I've repaired permissions and repaired the disk, to no avail.