[Dovecot] pop3+leave messages on server

hi All,

I have a srange problem.

Before dovecot there was a courier imap and it worked just fine. The client(s) are the same then before, so I think, this is an server side problem.

I have a user with Outlook and he uses pop3 and leaves messages on server.

Sometimes the messages get downloaded again, when he starts the outlook. Not all, but 7-9 hours back.

uidl format is like it's suggested:

pop3_uidl_format = %08Xu%08Xv

Any idea, what's wrong and what I can do?

Thank you very much,

tamas