Domain controllers are the backbone of any Active Directory domains in the Microsoft world. Any Windows server can be promoted to be a domain controller. In this article, we will go through the steps of promoting a Windows 2025 Server to be a domain controller.

Windows Server 2025

The latest version of the server operating system has been named Windows Server 2025. You can start with a 2025 Server & create an AD domain or you can promote a member server that is already a part of a domain.

The Windows Server 2025 needs to be installed on a machine before it can be promoted to be a domain controller.

Promote Windows Server 2025 To Domain Controller

If you have been working with Windows servers long enough, everything starts with the Server Manager app. Promoting a server to a domain controller is no different.

Launch ‘Server Manager’ & click on Add roles and features.

You land on the summary page that explains what is required to run this wizard successfully. Click Next.

Select Role-based or Feature-based installation and click Next.

Select the server that needs to be promoted and click Next.

Select Active Directory Domain Services (second option) and click on Add Features.

Go with the default options for features that need to be installed.

A summary of AD DS pops up next, click next to continue.

Select Restart the server automatically if required and click Install.

You get to keep an eye on the progress of the installation.

Once the role has been installed, you will find an exclamation mark on the top right corner of the Server Manager. Click on that and select Promote this server to be a domain controller.

You get an error straight away (which you have never seen before) – Error determining whether the target server is already a domain controller. Role change is in progress or this computer needs a restart.

We never needed to restart the server after installing the role in the DC promotion process. Given that it is an insider build of Server 2025, I am hoping that this will get fixed before the public release.

Restart the server, launch Server Manager and click on the Promote this server to be a domain controller option again.

I am setting up a brand new AD forest and hence I select the third option (Add a new forest) and enter my root domain name.

Next window brings the option to set your forest & domain functional level and the DSRM password. In the insider build, it shows what looks like a variable (the Windows server version on which the you are working).

You can leave the default options in the DNS options wizard and click next.

Enter the netbios name of the domain in the next window and click next.

You can stick with the default paths for the AD database, log & sysvol folder or pick a location of your choice.

Review the selections that you have made so far and click next.

Wait for the green check mark on the prerequisites page and click next.

Click Install in the final window & wait for the magic to happen. Once the machine gets restarted (which it will do automatically), you will have a brand new domain controller based on Windows Server 2025.

Summary

Promoting a Server 2025 to a domain controller follows pretty much the same steps as previous operating systems. The Insider build has few errors that needs to be fixed, but hey, it is an insider build!

Please let me know if you have any questions in the comments section.