Consider the following scenario:
You have a Microsoft Exchange Server 2010 Client Access server that has Update Rollup 5 for Exchange Server 2010 Service Pack 1 (SP1) installed in a mixed Exchange Server 2003 and Exchange Server 2010 environment.
Exchange ActiveSync device users connect to the Exchange Server 2010 Client Access server to access their mailboxes on Exchange Server 2003 servers.
In this scenario, the MSExchangeSyncAppPool application pool crashes on the Exchange Server 2010 Client Access server. Additionally, the following events are logged on the Exchange Server 2010 Client Access Server:
Log Name: Application
Source: MSExchange Common
Event ID: 4999
Task Category: General
Watson report about to be sent for process id: Process ID, with parameters: E12, Build Type, Version, AirSync, mscorlib, S.S.P.Win32.ImpersonateLoggedOnUser, System.ObjectDisposedException, XXXX, Version.
Log Name: System
Event ID: 5011
Task Category: None
Description:A process serving application pool 'MSExchangeSyncAppPool' suffered a fatal communication error with the Windows Process Activation Service. The process id was 'Process ID'. The data field contains the error number.
Note When this issue occurs, the Exchange ActiveSync device users cannot access their mailboxes.
This issue occurs because the Exchange ActiveSync ProxyHandler does not close anonymous connections between the Exchange 2010 Client Access server and the Exchange Server 2003 servers. Then, a System.ObjectDisposedException exception is thrown that causes the MSExchangeSyncAppPool application pool to crash.
To resolve this issue, install the following update rollup:
2645995 Description of Update Rollup 1 for Exchange Server 2010 Service Pack 2
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
For more information, click the following article number to view the article in the Microsoft Knowledge Base:
2556133 A device that uses Exchange ActiveSync cannot access mailboxes in an Exchange Server 2010 environment For more information, click the following article number to view the article in the Microsoft Knowledge Base:
2582113 Description of Update Rollup 5 for Exchange Server 2010 Service Pack 1 For more information about Exchange ActiveSync, visit the following Microsoft website: