Dcpromo Not Necessary for Cloning
Dcpromo.exe is the Microsoft utility that promotes a new Windows Server to run as an Active Directory domain controller. (On Windows Server 2012-2019, the PowerShell cmdlets Install-ADDSForest, Install-ADDSDomain, and Install-ADDSDomainController replace Dcpromo.exe.)
If you run Dcpromo it will attempt to create a new unrelated domain controller.
If you run Dcpromo on an isolated network, you will create an unwanted new domain controller and/or a new forest.
This is not harmful; it will simply take longer to clone AD. U-Move will overwrite the redundant information that Dcpromo created.
On Windows Server 2003, U-Move will reboot the computer to temporarily switch to Directory Services Restore Mode (DSRM) to remove the redundant information.
|U-Move for Active Directory|