RMS Shared Identity user FederatedEmail.4c1f4d8b-8179-4148-93bf-00a95fa1e042 not found


Exchange 2010 and Exchange 2013 includes different type of mailboxes like Discovery Mailbox, User Mailbox, Arbitration mailbox etc. FederatedEmail.4c1f4d8b-8179-4148-93bf-00a95fa1e042 is an arbitration mailbox that needs to be present in your Exchange organization for Exchange server installation. Mailbox guid of FederatedEmail will always remain the same i.e. “4c1f4d8b-8179-4148-93bf-00a95fa1e042“.

Let’s look at the issue that I have been having with my exchange 2007 to 2013 upgrade and how i fix it.


I have been working with one of my customer to upgrade their Exchange 2007 organization to Exchange 2013. During the Exchange 2013 installation, Mailbox Transport Services installation failed with the following error message.

RMS Shared Identity user FederatedEmail.4c1f4d8b-8179-4148-93bf-00a95fa1e042 not found

Looking at the error message we can see that we’re missing RMS Shared Identity user for Exchange 2013 installation. Possible reasons for this issue are as below.

  • Your Active Directory Preparation wasn’t done properly.
  • You deleted or moved the user account from Active Directory. RMS Shared Identity user account is created under default users organizational unit.

In my case, customer deleted the user account from ADSI Edit during the clean up of their AD to remove old installation footprint of their Exchange 2013.

How to fix it?

So now we know what is RMS Shared Identity and why we can have this issue in our organization when upgrading to Exchange 2013. Let’s take a look at on how we can fix this issue when you have this issue.

We got 2 methods of fixing this issue based on your exchange organization configuration.

  • Create user account manually
  • Re-run AD Preparation

To manually create a user account, go to Exchange 2010  and run Exchange management shell with administrative privileges. Run the following cmdlet.

New-Mailbox -Arbitration -Name FederatedEmail.4c1f4d8b-8179-4148-93bf-00a95fa1e042 -UserPrincipalName FederatedEmail.4c1f4d8b-8179-4148-93bf-00a95fa1e042@msexperttalk.com

It’s important to replace the msexperttalk.com domain name with your default SMTP domain.

Another method that i used with my customer is to re-run the Active Directory Preparation using Exchange 2013 setup. During the Active Directory preparation RMS Shared Identity user FederatedEmail.4c1f4d8b-8179-4148-93bf-00a95fa1e042 will be automatically created in default users organizational unit.

Similar issues were being reported for Exchange 2010 and you can find the details of those issues on Microsoft Support site.


  • great information

  • I think “re-run the Active Directory Preparation using Exchange 2013 setup” will only work if we create the user first.

    Well, nice troubleshooting.

    • Farooque,

      Thanks for your feedback. If you look at the details on what /PrepareAD switch do then you’ll notice that PrepareAD does create this account as part of AD Preparation. I’ve also mentioned the 2nd method of fixing this issue to manually create the mailbox. If you manually create the account then you don’t have to re-run AD Preparation. Hope this answers your question. Thanks.