[Dovecot] Duplicate e-mails

[Lisa Wu]

Hi,

I've got Postfix/Dovecot config mail server, POP3/mbox, and a few users are
complaining about duplicate e-mails. 

User connects with Outlook 2003 to Dovecot to download mail. If you check
the mail logs for that message ID, only one copy is delivered to his
mailbox. Also, verified that the client is set-up to NOT leave a copy of the
message on the server.

He downloads a copy of the e-mail once, and then 2 minutes later when his
client reconnects to check for mail, he gets another copy of that e-mail.
It's not a consistent problem.

I check the dovecot logs, and see his client connecting and disconnecting,
and always deleting the same number of e-mails it downloads. Is this a
network issue or a config issue? 

The only other thing to note is that it's usually an e-mail sent to a group
list that he's a member of. And I've set-up the owner-list setting in the
aliases file. So I don't think that's the problem.

If anyone can shed some light on this issue, it'd be greatly appreciated.

Thanks,
Lisa