When you go to Tools, Accounts how many POP3/IMAP accounts do you have listed?
Also how many of these accounts are also web based and do you have any of
these configured to forward mail to your WM inbox? Are you leaving email on
the server after you download it?
See where I am heading? Let's say you have Yahoo Mail Plus with POP3. You
have Yahoo Mail (web based) configured it to forward a copy of your messages
to WM. You also have it configured to leave a copy of the email on the
server. Then you set up your POP3 account in WM. When you synchronized WM
you would see the forwarded copy of the message from your web based account
and also it would download a copy of the message you left on the server like
normal.
Pretty far fetched, but the point I am making is that you need to post
information about your other accounts. Are you receiving 4 copies of all
messages or just some messages (depending on what other accounts they have in
common). For instance if you had a gmail and yahoo mail account configured
in WM and you got 4 copies of your gmail and only two copies of your yahoo
mail that might shed some light on the problem. I'm over my head when it
comes to tracking messsage headers, but if you can, look at the headers of
each message and see if they are coming from the same server or multiple mail
servers.
