The UID is defined in RFC for IMAP as needing to be a unique number for that mailbox. That is all it is. You can dump message files into an account and as long as they are "#." and you index them they will be visible to IMAP clients. The UIDL is related/derived number returned by POP. We actually had to patch our Cyrus install so it would return same UIDL results for POP as the old UW server, so transition from UW to Cyrus would be smooth. ---- Cyrus Home Page: http://cyrusimap.web.cmu.edu/ Cyrus Wiki/FAQ: http://cyrusimap.web.cmu.edu/twiki List Archives/Info: http://asg.web.cmu.edu/cyrus/mailing-list.html