The Microsoft knowledgebase article:
Describes this situation exactly except that the user in question is running OL2002 and is not using terminal services.
We're running Exchange2000, the user is on XP Pro SP1 with OfficeXP, all service packs applied. When this user is connected to the Exch server via the LAN and new mail arives, his OL2002 does not reflect this. if he clicks on any other folder in OL, then all folder status is updated and new mail is shown. This also happens when sending. If he sends and email, it will arive at the recievers mailbox but his outbox folder still shows one email pending (it has a bold number 1 next to it) until he clicks on another folder.
If I set up his exchange account on another PC with OL2002, it works fine..