We had our domain controller 2008r2 which was in USN Rollback mode. So we decided to decommission it.
We were able to transfer the fsmo roles to the secondary domain controller.
But it was impossible to depromote the server. So we followed the following tuto:
everything was OK except the command to remove the domain controller 2008 :

Because of this, we can not increase the level of the forest:

Thanks in advance

















