Event ID 10 messages fill up the Application log on an Exchange 2007 CAS server if an Exchange Server 2003 mailbox owner makes an Exchange Web Service call

When a Microsoft Exchange Server 2007 Client Access server (CAS) role is upgraded to Exchange 2007 Service Pack 1 in an Exchange Server 2003 and Exchange Server 2007 mixed organization, the following event message is generated every several minutes:

Event Type: Error
Event Source: MSExchange Web Services
Event Category: Core
Event ID: 10
Description:
CAS server <server name> running Exchange version 0.1 (8.0.535.0) attempted to find a CAS server in AD Site [Server not in site]. Service Discovery failed in looking up the CAS Server in the target AD Site.

These Event ID 10 messages fill up the Application log on the Exchange 2007 CAS server.

This issue occurs when a user account that has a mailbox that is hosted on an Exchange Server 2003 server runs certain Web service applications to issue commands against an Exchange 2007 CAS server. During this time, the CAS server makes an Exchange Web Service call and tries to contact the Exchange Server 2003 server. However, Exchange 2003 does not support Exchange Web Service calls. Therefore, Event ID 10 is generated in the application log of the Exchange 2007 CAS server.

To resolve this problem, install Update Rollup 5 for Exchange 2007 Service Pack 1. For more information about Update Rollup 5 for Exchange Server 2007 Service Pack 1, see the following Exchange Help topic: For more information about how to obtain the latest Exchange service pack or update rollup, see the following Exchange Help topic:

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.