We migrated from Exchange 2003 that was on a Server 2003 to Exchange 2007 on Server 2008. I don't know if this is a factor, but the Server 2008 that Exchange 2007 is on is a Virtual Machine running on XenServer 5. The old exchange server is a physical box. The Exchange 2003 has been removed from our domain . All of our workstations are XP Pro SP3.
The issue we have is all Outlook 2007 clients keep asking for credentials. And only the Outlook 2007. All of the user's (about 40 of them) that still have Outlook 2003 work just fine. We have only 5 user's that use Outlook 2007. We have changed the outlook confiuration in every combination. We have tried changing our passwords, recreating the outlook profile (with autodiscover and manually), removed the PC from the domain and readded, and every other suggestion I could find through Google. There are no event logs, error, or information that would give a clue as to what is causing this.
We have been working on this for weeks. We have an open ticket with Microsoft for close to a week and have heard nothing back.