Installation of RM Unify AD Sync fails with the following error message:

Error 1923. Service RM Unify AD Sync Sync Service (RM Unify AD Sync Service) could not be installed.  Verify that you have sufficient privileges to install system services.

This may or may not be accompanied by the error message below in the AD Sync log file:

User creation failed. user: identitysyncservce - System.UnauthorizedAccessException:  Access is denied

This is usually caused by the installing user account having insufficient administrative access to create the RM Unify AD Sync Service on the server and/or the identitysyncservice user account in the Active Directory (AD).

Occasionally, it can be caused by the existence of the RM Unify AD Sync Service from a previously failed uninstallation.

If installing RM Unify AD Sync on a domain controller, please ensure that the installing user account is a direct member of the following groups until installation is successfully completed:

• AD builtin Administrators group
• AD Domain Administrators group

If installing RM Unify AD Sync on a member server, please ensure that the installing user is a direct member of the following groups until installation is successfully completed:

• the member server's local Administrators group
• AD builtin Administrators group
• AD Domain Administrators group

1. On the RM Unify AD Sync server, run services.msc and check if RM Unify AD Sync Service is listed. If it is not listed then there is no need to follow the rest of this process.
2. Open 'Programs and Features'.
3. Check if RM Unify AD Sync is listed. If it is, select Uninstall and then repeat step 1 above to ensure that the service is no longer listed. 
4. If the service remains listed and RM Unify AD Sync is not showing under 'Programs and Features', proceed to the next step.
5. Run RM Unify AD Sync.msi.
6. Click Next.
7. If the License Agreement window appears, the installation wizard has not detected the pre-existing installation. Click Cancel and proceed to step 11 below.
8. If the Program Maintenance window appears, select Remove and click Next.
9. Click Remove, Finish.
10. Repeat step 1 above to confirm that the service is no longer listed. If it is still listed, proceed to the next step.
11. Open a command prompt as an administrator.
12. Type sc delete "RM Unify AD Sync Service" and press Enter.

If the service was in a Disabled state when the delete was requested, it may take a couple of minutes to complete. You can check that the delete message is pending action by attempting to repeat step 12 above. You should see the following message displayed:

"[SC] DeleteService FAILED 1072:

The specified service has been marked for deletion."