The RemoveDelegate operation of EWS fails, and then a "500 internal server" error response and event ID 4999 are logged in an Exchange Server 2007 server

Consider the following scenario:

• You have a computer that is running Microsoft Exchange Server 2007.
• You add a delegate to a principal's mailbox by using Microsoft Office Outlook or by using the AddDelegate operation of Exchange Web Services (EWS).
• You remove the delegate�s mailbox or you delete the delegate�s Active Directory account.
• You add other delegates to the principal�s mailbox by using the AddDelegate operation of EWS.
• You try to remove a delegate from the principal's mailbox by using the RemoveDelegate operation of EWS.

In this scenario, you receive a "500 internal server" error from the Exchange Server 2007 server when you call the RemoveDelegate operation of EWS. Additionally, the following event is logged in the Exchange Client Access server�s Application event log:

Log Name: Application
Source: MSExchange Common
Event ID: 4999
Task Category: General
Level: Error
Description:
Watson report about to be sent to dw20.exe for process id: <ID>xxxx, with parameters: E12IIS, buddy-RTL-AMD64, <version number>, WS, M.E.D.Storage, M.E.D.S.Rule.ParticipantFromAdrEntry, System.ArgumentException, <callstackHash>, <version number>. ErrorReportingEnabled: True

When a delegate's mailbox is deleted from the Exchange Server 2007 organization, the corresponding delegate entry in the properties of the principal's mailbox is not deleted. When you add other delegates by using the AddDelegate operation of EWS, this orphaned delegate entry is converted to NULL. Then, the later RemoveDelegate operation of EWS fails.

To fix this problem, install the following update rollup:

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

For more information about EWS, visit the following Microsoft Web site: