Exchange 2013 – Cannot Open Microsoft System Attendant Mailbox Error During Mailbox Move

A local mailbox move in Exchange 2013 fails with the error that the System Attendant Mailbox cannot be opened. I thought System Attendant was a thing of the past!


Cannot open Microsoft System Attendant Mailbox Error In Exchange 2013

Exchange 2013 doesn’t have system attendant mailbox or even the System Attendant service (mad.exe).

No System Attendant service in 2013

But, the error clearly mentions about the failure to open the attendant mailbox. Though System Attendant mailbox & service have been removed from Exchange 2013, the object is still present in the configuration partition.

System attendant object in config partition

But, that was not the cause of the error. Exchange 2013 has a new arbitration mailbox “Migration.8f3e7716-2011-43e4-96b1-aba62d229136” with a display name “Microsoft Exchange Migration”.

Migration arbitration mailbox

In my case, the database hosting this arbitration mailbox was dismounted for some reason. I mounted the database back and the move was successful. In short, this arbitration mailbox is required for successful mailbox moves.

If you have deleted it by mistake or it doesn’t exist in your Exchange (for whatever reason), you can always re-create the AD account by running Setup.exe/PrepareAD. Once the account is created, configure a mailbox for the account by running the command below.

Enable-Mailbox –Arbitration –identity “Migration.8f3e7716-2011-43e4-96b1-aba62d229136”

33 thoughts on “Exchange 2013 – Cannot Open Microsoft System Attendant Mailbox Error During Mailbox Move”

  1. Hi Rajith, am having same issue, arbitration mailboxes fine can even move them, but moving any mailbox get error:
    Cannot open mailbox /o=MyFirm/ou=Exchange Administrative Group (FYDIBOHF23SPDLT)/cn=Configuration/cn=Servers/cn=Exchange2007/cn=Microsoft System Attendant. Trying to enable-mailbox -Arbitration -Identity “Migration*” get following error:
    This task does not support recipients of this type. The specified recipient is of type UserMailbox. Please make sure that
    this recipient matches the required recipient type for this task.
    BTW moving from 2013 to 2019.

  2. In my case, I received the same error when moving a single mailbox into a new database meant to receive *just* that mailbox (my CIO’s. He fools with stuff often and breaks it. Hence, with his own database, he’ll only take himself out). Moving a 10.873GB mailbox generated more logging than the log drive for this database was sized for, so the migration stopped, giving the System Attendant error the OP mentioned. Dismounting and remounting the database fails, so the only elegant solution was to up the size of the log drive. In this case, I arbitrarily chose 20GB. Remounting was immediately successful, and the migration resumed on its own. All told, just shy 16.4 GB of logging was generated to move this box, so one suggestion is to turn on circular logging, if only during migrations that are expected to generate a bunch of logging.

    • Hi Jack,

      Circular logging is good, but be mindful that the last point you can go back for a restore is your last good backup.


  3. I am able to do mailbox moves, no problem. I get the error when I try and create a Resource mailbox.

    Here are the 5 arbitration mailboxes I have:

    All mailbox databases are mounted and DAG copy is healthy. I can create a user mailbox, but not a Resource mailbox. Very strange. This is a new build Active Directory and Exchange 2013 CU8. I don’t have this problem in any of the other environments I manage (15 total).

  4. Arbitration mailbox by default disabled. Why these are disabled account in AD.

    If I am trying to enabled this mailbox, It showing error through exchange shel”task does not support recipientss of this type”

    If I am trying to enable through DSA.msc, It showing unable to update the password.

    These account should be disabled or enabled.

  5. Hello Rajith,

    cool website here ;-).

    We have the same exact problem from Joel. All five arbitration boxes are available.
    Is the problem from Joel resolved yet?

    Thanks in advance.


  6. Get-Mailbox -Arbitration lists nothing in my Ex2013 environment. Neither is there any Exchange Migration acccount listed in AD. Can this account only be created by running Setup.exe/PrepareAD. What is the impact of this? Thx

    • Hi ST,

      Yes, the account gets created as part of the AD prep. There is no harm in running the prep again.

      • Ran setup.exe /adprep and i got no new arbitration mailboxes (i am missing 3 i think).

        Name Alias
        —- —–
        SystemMailbox{bb558c35… SystemMailbox{bb5…
        Migration.8f3e7716-201… Migration.8f3e771…

      • Hi Joel,

        Please email me using the contact form. Or you can have the image uploaded in a public domain like pastebin dot com

    • For me the solution below worked, as I had found I indeed had a quarantined mailbox via the event log in Windows Server, still not sure what mailbox it was:

      Resetting a quarantined mailbox
      It is possible to reset a quarantined mailbox by deleting the quarantine registry key for that mailbox located at:

      HKLM\SYSTEM\CCS\Services\MSexchangeIS\Servername\Private-dbguid\Quarantined Mailboxes\ {Mailbox guid}.

      The database then has to be dismounted and remounted or the IS service restarted for the reset to take effect immediately. Unless the underlying issue is not resolved, the mailbox could crash the store and become quarantined again.

      I dismounted the database and remounted. Voila, no more error message when going into Migration in EAC.

  7. Hi Rajith,

    I’ve recently installed Exchange 2013… mind you i have an existing 2007 environment where all our users connect to. I have successfully migrated 10 mailboxes from 2007 to 2013 with no issues… Today I decide to take a look at the resources tab on exchange 2013. I show all of them in there but when i click on any them i receive the following error:

    Cannot open mailobx /o=Firm/ou=Exchange Administrative Group (FYDIBOHF13SL!!)/cn=Configuration/cn=Servers/cn=Exchange2007Firm/cn=Microsoft System Attendant.

    Any reason why?

    • Hi Joey,

      As explained in the article, do you have all five arbitration mailboxes? Run Get-Mailbox -Arbitration in 2013 Shell and paste the output here to help you better.


      • Thanks for the quick response Rajith. BTW awesome website!

        [PS] C:\Windows\system32>Get-Mailbox -Arbitration

        Name Alias ServerName ProhibitSendQuota
        —- —– ———- —————–
        SystemMailbox{1f05a927… SystemMailbox{1f0… ex2013firm Unlimited
        SystemMailbox{e0dc1c29… SystemMailbox{e0d… ex2013firm Unlimited
        FederatedEmail.4c1f4d8… FederatedEmail.4c… ex2013firm 1 MB (1,048,576 bytes)
        SystemMailbox{bb558c35… SystemMailbox{bb5… ex2013firm Unlimited
        Migration.8f3e7716-201… Migration.8f3e771… ex2013firm 300 MB (314,572,800 bytes)

        • That looks fine to me Joel.

          When do you get the error? When you try to move a mailbox? Between 2013 or with legacy?
          Bit more info please.

          • Well the resources are a bit different right. When I click on Recipients—Resources— and I try to click one the conference I get that error.

            Cannot open mailbox /o=MyFirm/ou=Exchange Administrative Group (FYDIBOHF23SPDLT)/cn=Configuration/cn=Servers/cn=Exchange2007/cn=Microsoft System Attendant.

  8. Also, keep in mind the logging for the Database where the migration mailbox resides. if you are doing a lot of moves, the logs will start to increase. so Either plan your moves in between backups to flush the transaction logs of the DB that holds the migration mailbox, or set Circular logging on the DB that holds the migration mailbox


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