I created a Smart Mailbox to filter my inbox for all mail from American Airlines. It worked perfectly - yesterday. When I checked my mail this morning the American Airlines folder only had 10 emails in it. 9 of them were from an old mailbox from 2006 and 1 that arrived today. All the rest of them, a hundred or so, were gone. They are also gone from the inbox. I can't find them anywhere. I tried rebuilding the mailbox to no avail. Any suggestions?