I am running Exchange 2000 with all available SP. The problem is that newly created users / mailboxes are not resolving when I'm trying to set them up in Outlook 2000. I have about 400 mailboxes on the server. Every mailbox that was created PRIOR to yesterday is absolutely fine. Another oddity is that these NEW mailboxes CAN login via OWA. It's just the Outlook MAPI client that fails. Any thoughts? Thanks in advance.