getting two copies of all e-mails
I get two copies of all e-mail.
iMac, OS X Mountain Lion (10.8.3)
I'm going to assume this is mail sent out...
Is {Mail.app > Mail > Preferences > Composing > automatically CC/BCC myself} set?
If not, could you put a few more words around what's happening, and which address(es) are in the message headers for the mail?