When installing Exchange 2013, installation of the Mailbox Transport role failed with the following error:
The following error was generated when R20;$error.Clear();
if ( ($server -eq $null) -and ($RoleIsDatacenter -ne $true) )
Update-RmsSharedIdentity -ServerName $RoleNetBIOSName
R21; was run: “RMS Shared Identity user FederatedEmail.4c1f4d8b-8179-4148-93bf-00a95fa1e042 not found.”.
FederatedEmail.4c1f4d8b-8179-4148-93bf-00a95fa1e042 is a Exchange 2013 built in arbitration user account which must exist in every Exchange 2013 environment. The GUID never changes, it is always R20;4c1f4d8b-8179-4148-93bf-00a95fa1e042”.
The setup failed because someone deleted this user account from Active Directory!
How can we get it back?
You have two ways to get this mailbox back. If you have a computer on your network with the Exchange 2010 management tools installed, you can create the user account using powershell with the following command:
New-Mailbox -Arbitration -Name FederatedEmail.4c1f4d8b-8179-4148-93bf-00a95fa1e042 -UserPrincipalName FederatedEmail.4c1f4d8b-8179-4148-93bf-00a95fa1e042@default_accepted_domain
For more information on this see Microsoft KB978776
What happens if you do not have exchange management shell installed on any computers? Well there is another way to get this account back. This account is originally created when you prepare the domain/schema. If you run setup.com /PrepareAD on your domain it will re-create this account for you. See below: