Since upgrading to Mountain Lion my Apple Mail software sometimes does not receive some mail. I started checking my mail with Thunderbird & found that 1 or 2 messages that appeared in Thunderbird never appeared in Mail, not in Inbox, Junk, nor in Trash. The emails are personal, not commercial ads, and sometimes I will receive one from the same person, same day that Mail rejects another one from. I am having to check 2 email programs just to make sure I don't miss important emails. This has been happening about 5 or 6 times a week since my upgrade to mountain lion. Any suggestions?
MacBook Pro (15-inch Early 2011), OS X Mountain Lion (10.8.2)
