Microsoft has released Cumulative Update 11 for Exchange Server 2013.

From the Microsoft Exchange Team blog:

The release includes fixes for customer reported issues, minor product enhancements and previously released security bulletins. A complete list of customer reported issues resolved can be found in Knowledge Base Article KB3099522. Customers running any previous release of Exchange Server 2013 can move directly to Cumulative Update 11. Customers deploying Exchange Server 2013 for the first time may skip previous releases and start their deployment with Cumulative Update 11 directly.

Cumulative Update 11 does not include updates to Active Directory Schema, but may add additional RBAC definitions to your existing configuration. PrepareAD should be executed prior to upgrading any servers to CU11. PrepareAD will run automatically during the first server upgrade if Setup detects this is required and the logged on user has sufficient permission.

Cumulative Update 11 also includes a change in behavior when deploying/administering Exchange Server 2013 in a co-existent manner with Exchange Server 2010 or 2016. These changes are outlined in the following blog article: Exchange Management Shell and Mailbox Anchoring.

The changed behavior for PowerShell management is important if you have a co-existence deployment, and in particular a geographically distributed deployment. You may need to do some internal education with your IT team, and review any scripts or other tools that rely on PowerShell access to Exchange.

An important article to read is Andrew Higginbotham’s explanation of how mailbox anchoring affects new installs and upgrades.

Also note that CU11 fixes the bug that allowed an Exchange 2016 mailbox server to be added to an Exchange 2013 DAG.

Cumulative Update 11 is available for download here.

For deployment steps refer to this guide to installing cumulative updates for Exchange Server 2013.

About the Author

Paul Cunningham

Paul is a former Microsoft MVP for Office Apps and Services. He works as a consultant, writer, and trainer specializing in Office 365 and Exchange Server. Paul no longer writes for


  1. Muffaddal Hussain

    Hii, Mr. paul,

    I have 2 exchange Server 2013 active and passive DAG. When I create a mailbox in EAC and add this email account for domain users outlook as separate email account, it keep prompting for password again again. Even after restarting the computer and login, it prompts for windows security for domain account email id , sometimes the newly one created. I already checked the password prompt option is disabled and selected Anynomous . In Outlook http , it is NTLM authentication. Please help..

    1. Avatar photo
      Paul Cunningham

      Users need to authenticate to access a mailbox. I’m not sure what you’re expecting to happen there, or why you’re trying to do it that way.

  2. Eric

    We have come across an issue when we try to upgrade a EX 2013 MBX server from CU 5 to CU 11. Find logs below. Please shed some light in this if possible.

    The following roles have been unpacked: BridgeheadRole ClientAccessRole MailboxRole UnifiedMessagingRole AdminToolsRole
    [04/20/2016 06:11:31.0475] [0] The following datacenter roles are unpacked:
    [04/20/2016 06:11:31.0490] [0] The following roles are installed: BridgeheadRole ClientAccessRole MailboxRole UnifiedMessagingRole AdminToolsRole
    [04/20/2016 06:11:31.0537] [0] [ERROR] Exception has been thrown by the target of an invocation.
    [04/20/2016 06:11:31.0553] [0] [ERROR] Requested value ‘15.0.913.22’ was not found.
    [04/20/2016 06:11:31.0553] [0] CurrentResult SetupLauncherHelper.loadassembly:444: 1
    [04/20/2016 06:11:31.0553] [0] The Exchange Server setup operation didn’t complete. More details can be found in ExchangeSetup.log

  3. Peter

    NetApp SME 7.2 (SnapManager for Microsoft Exchange) is also not compatible with CU11.

  4. mayur hadke

    Hi all
    i am getting the following error while up gradation of Exchange 2013 to CU11

    Please help me on this

    Mailbox role: Unified Messaging service FAILED
    The following error was generated when “$error.Clear();
    ” was run: “The task failed because a Win32 error occurred: “The specified service has been marked for deletion”
    . Failed to change the optional configuration parameters of service “MSExchangeUM”.”.

    1. pjmartins

      Mayur, did you resolve this as i’m getting the same on CU15 update from CU14.


      1. Stefan

        did you resolve this ?

        Mailbox role: Unified Messaging service FAILED
        The following error was generated when “$error.Clear();

  5. Aleksey

    @Cris and to all.

    Today we have faced with the same issue. We have Veritas/Symantec Netbackup, and we updated CU7 to CU11, and didn’t have an ability to prepare incremental or full backups.
    So we contacted to the vendor and it shared new KB with us:
    This is really working solution.
    (Please not the article was published on 12 feb 2016 – very fresh)

    In Exchange versions prior to 2013 CU11 and 2016 CU1, Exchange Management Shell session typically connects to the local server where the shell is opened, and to a proxy only when required.

    Exchange 2013 CU11 and 2016 CU1 introduces a new functionality called mailbox anchoring: Instead of connecting locally, Exchange Management Shell session will now be proxied to the server where the user’s mailbox is located. If the user does not have a mailbox, an arbritration mailbox is used instead and the session will be proxied to the server where that arbitration mailbox is located. This new behavior may cause backup to fail, since part of the process involves querying Exchange topology using PowerShell.

    For more information on mailbox anchoring, refer to:
    ===END CUT===

  6. Chris

    Veritas Netbackup 7.6.x not compatible….
    Having this issue now..

  7. Novih

    Hi Paul,

    if I update my environtment to CU11, whether there will arise a problem ?
    have you update your environment user CU11 ?


    1. Avatar photo
      Paul Cunningham

      As long as you understand the mailbox anchoring issues. Other than that, I don’t know of any particular bugs or problems with CU11.

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