We recently migrated from Exchange 2003 to Exchange 2010 with no service packs. Within our Organization we have two replicas of PF's. When clients do a lookup for attendees some comeback with details while others show no info. Then perform the same action say one hour later and get different results. If you perform a cleanfreebusy on Outlook client info is present then by end of day no info is displayed. Clients are using Outlook 2003 SP3 or Outlook 2007 SP2.

Is the behaviour identical between Outlook 2003 and 2007? As they query the free/busy information in different ways. If you query the public folder information using get-publicfolderstatistics, do the OAB virtual directories have an identical item count? SimonSimon Butler, Exchange MVP Blog | Exchange Resources

Hi, Whether all the mailboxes were migrated from the Exchange 2003 to Exchange 2010? If they were, Outlook 2007 clients connected to Exchange 2010 mailboxes to get the Free/busy via the Availability service, but Outlook 2003 clients retrieve the free/busy via the Public Folder. That's the difference. You mentioned the Outlook /cleanfreebusy can temporary relieve this issue, could you tell me which side you run the commmand? Organizer or Attendee? Thanks AllenAllen Song

The stats of OAB virtual directories for version 2 & 3 were identical (64). Version 4 had (36). The problem happens mostly for Outlook 2003 clients when looking up attendees. We have two copies of Public folders on a mailbox server and one copy on an Exchange 2003 BE server. Is there a way to do a trace where clients are getting freebusy details from? Also could I set logging to verbose to get better information why, when, and how?

Hi, Is the issue same in OWA? Please try to test the issue in OWA. To track the free/busy logging, you can enable Outlook Logging to capture it: http://support.microsoft.com/kb/841615 For Outlook 2003 client, it contacts the mailbox server of the attendee to inquire about the location of the associated public store, then locates of the free busy public folder based on the user's LegacyExchangeDN. Thanks AllenAllen Song