Admin sessions are exhausted as a result of delegate access in an Exchange Server 2010 environment

Aplica-se a: Exchange Server 2010 StandardExchange Server 2010 Enterprise


Consider the following scenario:
  • You install Microsoft Exchange Server 2010.
  • You delegate some management roles.
  • The delegates have Full Access permissions to some mailboxes.
  • The delegates perform actions on the mailboxes at the same time.
  • The actions generate copy-on-write delegate access requests and create many admin sessions. For example, more than 10,000 admin sessions are created.
  • You try to run an Exchange Server cmdlet. For example, you try to run the Test-MapiConnectivity cmdlet to verify server functionality in a mailbox.
In this scenario, the cmdlet may fail. For example, one or more of the following events are logged in the Application log when you try to run the Test-MapiConnectivity cmdlet:


This problem occurs because the maximum number of admin sessions on the Exchange Server 2010 mailbox server is 10,000. Therefore, no more admin session can be created when 10,000 copy-on-write delegate access requests to the mailboxes are issued.


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 the Test-MapiConnectivity cmdlet, go to the following Microsoft website:


For more information about Update Rollup 4 for Exchange Server 2010 Service Pack 2, click the following article number to view the article in the Microsoft Knowledge Base:

2706690 Description of Update Rollup 4 for Exchange Server 2010 Service Pack 2