The specified active directory user already exists as a crm user.

We came across this error, when we were trying to Add new user into the CRM.

"The specified Active Directory user already exists as a CRM user"

"You are attempting to create a user with a domain logon that is already used by another user. Select another domain logon and try again."

This kind of error comes when you moved your database from other organization. Solution for this is explained below:

Note: This is unsupported way for the resolution. Please take a backup of both Config DB as well as MSCRM DB.

Solution 1: Please check whether the User you are trying to add is disabled. Change the view to disabled user, as the search on User entity in CRM work only for Enabled user.

Solution 2: (Unsupported)

       1.       Get SID for AD-user

1.1   Open Windows Powershell (Run as Administrator)

1.2   Type below command in the window.

$AdObj = New-Object System.Security.Principal.NTAccount("USERNAME")

$strSID = $AdObj.Translate([System.Security.Principal.SecurityIdentifier])

$strSID.Value

       2.       Login to SQL server (Config DB)

2.1   SIDs are stored in SystemUserAuthentication table of Config DB where it is being prefixed with “W:” where I think W may be referring as Windows.  Get the UserId for the SID which we identified in step 1.

select UserId,* from SystemUserAuthentication where

AuthInfo ='W:SIIDFromStep1'

       3.       I found the OrganizationId by querying the Organization table.

select Id,UniqueName from organization

       4.       I then found the SystemUserOrganizations record for the intersection of their user CRM user ID and the Org ID by running the following query:

select * from SystemUserOrganizations

where OrganizationId = 'OrganizationIDFromStep3'

AND UserId = 'UserIDFromStep2'

       5.       Backup MSCRM_CONFIG database & SystemUserOrganizations table using:

select * into SystemUserOrganizations _bak  from SystemUserOrganizations

       6.        I then deleted the SINGLE record identified in step 4.

delete from SystemUserOrganizations

where OrganizationId = 'OrganizationIDFromStep3'

AND UserId = 'UserIDFromStep2'

       7.       I went and added my user.

Again, this worked for me. I hope this helps someone else out, but your mileage may vary and don't blame me if things get messed up. :)