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:
Time: Time ID: 14035 Level: Error Source: MSExchange MailTips Machine: Computer Message: Process Microsoft.Exchange.InfoWorker.Common.Delayed`1[System.String]: MailTips query failed for mailbox Mailbox. Latency: total:7. The returned exception is: Microsoft.Exchange.Data.Storage.TooManyObjectsOpenedException: Cannot open mailbox /o=Organization/ou=Exchange Administrative Group (FYDIBOHF23SPDLT)/cn=Configuration/cn=Servers/cn=Computer/cn=Microsoft System Attendant. ---> Microsoft.Mapi.MapiExceptionSessionLimit: MapiExceptionSessionLimit: Unable to open message store. (hr=0x80040112, ec=1246)
Time: Time ID: 1006 Level: Warning Source: MSExchange Mailbox Replication Machine: Computer Message: The Microsoft Exchange Mailbox Replication service was unable to process jobs in a mailbox database. Database: Database Error: MapiExceptionSessionLimit: Unable to make connection to the server. (hr=0x80040112, ec=1246)
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.
To resolve this issue, download and install Update Rollup 4 for Exchange Server 2010 Service Pack 2. For information about how to download and install Update Rollup 4 for Exchange Server 2010 Service Pack 2, visit the following Microsoft website: