It appears you have 2 pop configurations or 1 pop and one Imap or a pop/imap configuration and you decided to forward a copy of email...or your profile could be corrupted.

Either way, you need to remove one. The easiest thing to do is to go to Tools > Account Settings and see what's there.

Reconfiguring a new profile will fix most problems.

Hope this helps!

yeah I had this too, just remove the accounts you dont use... or if you only have 1 or 2, remove everything and start from zero.