I have a user account which has an external POP account. The account is setup to delete mail off the server, but it isn't. I continually downloads messages over and over again (he has more than 45,000 messages since he was polling every 60 seconds.
We had this happen on Friday, but it was only a few emails coming in over and over. Our ISP (who hosts this POP account) said the mail server was logging in twice within four seconds (back to back) but getting an error and not deleting the mail. At that point, I had the ISP delete the mail manually, and it seemed to be working fine at that point.
Now however, there appears to be something really wrong. Any ideas? There don't appear to be any errors in mailbox.log.