Symptoms
After you move mailboxes that contain Information Rights Management (IRM) protected email messages to a Microsoft Exchange Server 2010 Service Pack 1 (SP1) mailbox server, the Microsoft Exchange Mailbox Assistants service (MSExchangeMailboxAssistants.exe) crashes frequently. Additionally, the following event is logged in the Application log:
Log Name: Application
Source: MSExchange Common
Date: Date
Event ID: 4999
Task Category: General
Level: Error
Keywords: Classic
User: N/A
Computer: Computer
Description:
Watson report about to be sent for process id: Process ID, with parameters: E12, Build Type, Version Number, MSExchangeMailboxAssistants, M.E.Data.Storage, M.E.D.S.RightsManagedMessageItem.EnsureIsDecoded, System.InvalidOperationException, XXXX, Version Number.
ErrorReportingEnabled: False
Cause
This issue occurs because the conversation assistant cannot handle IRM-protected messages that are not decoded when it tries to create conversation view after the mailbox is moved.
Resolution
To resolve this issue, install the following update rollup:
2645995 Description of Update Rollup 1 for Exchange Server 2010 Service Pack 2
Status
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
More Information
For more information about Information Rights Management (IRM), visit the following Microsoft website:
General information about Information Rights Management (IRM)
