You create an exception to the recurring meeting request by using a Collaboration Data Objects (CDO) application
In this scenario, you find an E_FAIL 80004005 error occurs which blocks the operations. At the same time, the Exchange RPC Client Access service crashes. Additionally, you find the following error in the Application log:
Source: MSExchange Common Event ID: 4999 Task Category: General Level: Error Description: Watson report about to be sent for process id: <process ID>, with parameters: E12, <build type>, <application Version>, RpcClientAccess, M.Exchange.Data.Storage, M.E.D.S.MapiAttachmentProvider.ExistsInCollection, System.NullReferenceException, <callstackHash>, <assembly Version>.
To resolve this problem, install Update Rollup 1 for Exchange Server 2010.
976573 Description of Update Rollup 1 for Exchange Server 2010
Note You have to apply this rollup package on all related CAS servers.