Consider the following scenario. You have a mixed Microsoft Exchange Server 2003 and Microsoft Exchange Server 2010 environment. You migrate mailboxes from an Exchange Server 2003 server to an Exchange Server 2010 server. In this scenario, certain free/busy messages are not replicated from the Exchange Server 2010 server to the Exchange Server 2003 server. Therefore, the updated free/busy messages of the migrated mailboxes are not available on the Exchange Server 2003 server.
Additionally, the following event is logged in the Application log on the Exchange Server 2003 server:
Event Type: Error
Event Source: MSExchangeFBPublish
Event Category: General
Event ID: 8207
Description: Error updating public folder with free-busy information on virtual machine <server name>. The error number is 0x80070057.
This issue occurs because Exchange Server 2010 uses specific properties to process free/busy messages. However, Exchange Server 2003 does not process these messages well.
To resolve this issue, install the following update rollup:
2608646 Description of Update Rollup 6 for Exchange Server 2010 Service Pack 1
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
For more information about a similar issue, click the following article number to view the article in the Microsoft Knowledge Base:
955443 Some free/busy messages are not replicated from Exchange 2007 to Exchange 2003 servers after some mailboxes are migrated from Exchange Server 2003 to Exchange Server 2007