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How to Remove a DAG Member in Exchange Server 2013

When you are running an Exchange 2013 database availability group in your environment you may have a need to remove one of the servers from the DAG, for example during decommissioning of server hardware.

If you were to try and simply uninstall Exchange 2013 from the server you would encounter an error during the readiness checks.


This computer is a member of a database availability group (DAG). It must be removed from the DAG before you can uninstall Exchange.

Following that advice if you were to try and remove the server from the DAG you may encounter this error.


Mailbox server ‘E15MB3’ cannot be removed from the database availability group because mailbox database ‘Mailbox Database 1’ has multiple copies. Use Remove-MailboxDatabaseCopy either to remove the copy from this server or to remove the copies from other servers in the database availability group.

By now I’m sure you realise that there is a process that needs to be followed before you can uninstall Exchange 2013 from the DAG member.

  1. Removing database copies
  2. Removing the Exchange server from the DAG

Let’s take a look at those steps in more detail.

Removing Database Copies

The first part of the process is the removal of database copies. There are actually two approaches here.

  1. If you are planning to remove the server from the DAG but keep it as a standalone server hosting databases, then any copies of those databases must be removed from other DAG members first.
  2. If you are planning to completely uninstall Exchange 2013 from the server then any database copies should be removed from the server that is being uninstalled.

Technically you could use the first approach even if you plan to completely uninstall the server, but even after removing the server from the DAG you won’t be able to uninstall Exchange 2013 if it still hosts databases that contain mailboxes.

See Exchange 2013 Database Removal Error: “This mailbox database contains one or more mailboxes” for more information.

So it makes sense to use the second approach for a server that is being completely decommissioned, which is the scenario I will be using for the rest of this tutorial.

In the Exchange Admin Center navigate to Servers -> Databases and select a database that has a copy on the server you are removing from the DAG.


If it happens to be the active database copy you would see an error and you must first switchover the database to another DAG member.

The database “Mailbox Database 3” is currently hosted on server “E15MB3”. Use Move-ActiveMailboxDatabase to move the active copy of the database to a different server.

Click the Remove link for the database copy.


If you have multiple database copies to remove you can use this PowerShell command to remove them all. Again, this command won’t work if the database copy is active or if it is the only copy of the database.

Removing the Server from the Database Availability Group

After removing all database copies from the DAG member the next step is to remove it from the DAG itself.

In the Exchange Admin Center navigate to Servers -> Database Availability Groups. Select the DAG and click the Manage DAG Membership button.


Highlight the server name and click the Remove button.


Click Save to complete the removal process.

You can also remove the DAG member using PowerShell.

Removing Exchange Server 2013

Now that the Mailbox server has no databases and has been removed from the DAG, and assuming the server performs no other roles in your organization, you can uninstall Exchange 2013.


Paul is a Microsoft MVP for Office Servers and Services. He works as a consultant, writer, and trainer specializing in Office 365 and Exchange Server. Paul is a co-author of Office 365 for IT Pros and several other books, and is also a Pluralsight author.
Category: Exchange Server


  1. Jonby says:

    Just want to say thank you. This “How To” made me more comfortable when I decommission one of our server out of the DAG last night. We actually have Exchange 2010 but same steps. Very detailed and easy. Thanks again.

  2. Hein Traag says:

    We were almost ready with setting up our new Exchange 2013 servers when we did a fubar action and one of us decided to delete the newly created servers and start installing from scratch. We now stil see the ‘old’ new exchange 2013 servers and dag group. Next to the 2010 servers and the ‘new’ 2013 servers and dag group.

    The failed 2013 servers are not there anymore.. how do we remove them from the list in the ECP? If you have any ideas on that we would love to know about it.


      • Hein says:

        Thanks Paul for the answer.

        Just to make sure i understand correctly.. we install two new servers with the exact same names as the old servers. Install Exchange on them and them do a clean uninstall?

        If that is it then we should be done in no time at all.

        Thanks for the answer and thanks for a truly helpfull website.

        • Hein Traag says:

          Great. Will do just that then. Thanks for the info.

          Adding this to try and recover the migration mailbox. Apparently after installing the two new servers my now ex-colleague had removed the mailbox database on server 2. Which results in not being able to migrate mailboxes using the ECP.

          Manual commandline migration does work. Any idea on how to restore a migration mailbox so we can batch migrate using ECP?

  3. Rahamathullah says:

    I want to uninstall one of my DAG member server. it has mailbox/ CAS role on it. above steps should be followed for the same.

  4. Shahan says:


    How I can resolved mention issue,

    Passive Healthy
    Copy queue length: 0
    Content index state: Unknown
    Suspend | Activate | Remove
    View details

    I create a dag and when above database is copying from One Exchange server to another so it stuck and content index state is unknown. Please tell me how I can resolve this issue.


  5. Trent says:

    Fantastic walk-through! Thank you for putting these together Paul, always incredibly helpful!

    Quick question, if you have a second. Have you ever seen the issue when trying to remove a server from a DAG that the server must be running exchange? Exchange is definitely installed on the server, so I’m not sure what the deal is. I have managed to get both database copies deleted

  6. paul williams says:

    If exchange is uninstalled properly off the decomm server is there any need to remove anything from ADSI afterwards?

  7. paul williams says:

    What if server is also CAS? Is there any way to keep the message tracking logs that would otherwise be lost?

  8. Tarig Mustafa says:

    Dear Paul
    Thank you for this tutorial
    I have 3 member on dag all run exchange 2013, one of server on different site on active directory site, on that site also we have domain controller but it off, the problem on that site is exchange service like replication services won’t running so I have on eac on database bad copy, if I plane to fix it should I remove it from dag and rejoining it again?

  9. Tarig Mustafa says:

    Dear I did start the Domain controller
    and their is issue with service :
    MSExchangeEdgeSync , MSExchangeFrontEndTransport , MSExchangeMailboxReplication , MSExchangeDelivery , MSExchangeSubmission , MSExchangeRepl , MSExchangeRPC , MSExchangeFastSearch , MSExchangeThrottling , MSExchangeTransport .
    all this service not able to start even after run this command in power shell
    Get-Service *exchange* | Start-Service
    if I try to open exchange management shell it open but connect to other active member on dag

    I really appreciate your helpful support

    • Tarig Mustafa says:

      In EAC this server DRex01 status is unknown if I open details it says service down and on error message section :
      A server-side administrative operation has failed. The Microsoft Exchange Replication service may not be running on server Drex01.domain.com . Specific RPC error message: Error 0x6d9 (There are no more endpoints available from the endpoint mapper) from RpccGetCopyStatusEx4

      • If your services won’t start there’s probably still a problem with the domain controller, probably from being left turned off. You could try deploying a new DC to that site. You could try simply rebooting the Exchange server. Otherwise you should consider opening a support case with Microsoft.

        • Tarig Mustafa says:

          Thanks Paul
          if I can find any way to remove it form dag and rejoin it
          the database in that server is out of date so their is no harm to remove it
          from EAC their is no option to remove it

          I really appreciate your helpful support

          • I don’t actually understand what you’re saying there.

            I can only give you general advice here. I can’t see your environment or the errors that you’re experiencing, so if you can’t describe them clearly then I can’t help you very much.

            If you’re not able to work out a solution to your problem you should open a support case with Microsoft.

  10. Augsuto says:

    I have the problem, exchange doesn’t can be removed, my Witness server and one member from DAG have problems on Hardware (i can’t power on), i need to change the witness server and remove the DAG member.

    I can’t remove the DAG member, because it can’t contact the Witness server for removal, and i cant change the Witness server.

    I need to up two different servers and point as the same name? After this, remove those servers from DAG ?


  11. Srinivas says:

    Hi Paul,

    We have 4 Exch 2010 servers in DAG with 1+3 copies of Database. We want to remove two servers from the 4 Node DAG and keep 1+1 copy of database. File share witness is on the HUB/CAS server. Will it be a straight forward steps to remove databases first and then delete the nodes from using Manage DAG Membership and then uninstall the servers. Suggestion appreciated.


  12. Alex says:

    I had 4 Exchange server in DAG.
    I don’t have Exchange server anymore (Don’t ask how it’s happened)
    Now i run setup with key -RecoverServer but I get error:
    The Exchange server is a member of a database availability group.
    How remove member of DAG with using ADSIEdit?

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