When this error occurs, you will be unable to promote the server to DC. It should be noted that this issue is expected to occur if you’ve Active Directory Certificate Services (AD CS) installed.
Verification of prerequisites for Domain Controller promotion failed
DCPromo (Domain Controller Promoter) is a tool in Active Directory that installs and removes Active Directory Domain Services and promotes domain controllers. DCPromo, which builds forests and domains in Active Directory, is found in every version of Windows Server since Windows 2000. In the event you’re faced with this issue, you need to perform a 3-step fix which involves you first remove the ADCS role. Secondly, you then promote the server to DC. And thirdly, you can now reinstall the AD CS role. Let’s take a look at the step-by-step guide. Do the following:
Open Server Manager.Click Manage.In the context menu, select Remove Roles and Features.In the Remove Roles and Features Wizard, click Server Roles on the left pane.Under the Roles pane in the middle of the Wizard, uncheck Certification Authority under Active Directory Certificate Services.On the pop-up that appears, click Remove Features button.Next, you can click the Close button to exit Remove Roles and Features Wizard when you see that your selected roles for Active Directory Certificate Services has been removed.
Now you can retry promoting the server to Domain Controller – this time, the operation should complete successfully without any error. Once you have successfully promoted the server to Domain Controller, you can then reinstall the Active Directory Certificate Services (AD CS), which we removed in the previous step. Hope this helps!
