When you try and run DCPromo from the explorer shell on Windows Server 2012, you will receive the following message "The Active Directory Domain Services Installation Wizard is relocated in Server Manager. For more information, see http://go.microsoft.com/fwlink/?LinkId=220921."
No DCPromo, what now?! DCPromo is deprecated in Windows Server 2012, so adding an additional Domain Controller is slighter different than in earlier versions. The new process is still straight forward, and the wizard will even extend the schema (to version 56) for you- meaning it's a one-stop process. Adding a Windows Server 2012 Domain Controller requires a Windows Server 2003 forest functional level or higher on your existing forest.
Promoting a Server 2012 to a Domain Controller
1. Open Server Manager, select Local Server on the left hand side then choose Manager -> Add roles and Features.
2. Next.
3. Next.
4. Select the server you wish to promote.
5. Tick Active Directory Domain Services.
6. Click Add Features.
7. Next.
8. Next.
9. Install.
10. In Progress.
11. Close.
12. You'll now notice you have a notification, prompting you to promote this server to a domain controller.
13. We are adding a domain controller to an existing domain, specify the domain and domain administrator credentials.
14. It will make the additional DC a DNS and GC by default, we do not want to make this a Read Only Domain Controller. You have the option to add the DC to a particular Site. Enter your DSRM password (as usual, keep this safe!).
15. You can typically ignore the warning about DNS delegation, a more detailed explanation can be found here: http://technet.microsoft.com/en-us/library/cc754463(WS.10).aspx
16. You can install from Media, which is useful if you are promoting a DC in a branch office with a poor connection- it will significantly reduce the initial Active Directory replication. You can specify a particular DC for the initial replication.
17. Default locations.
18. This screen tells us it will prepare the Forest, Schema and domain for us (Server 2012 uses Schema Version 56).
19. Review screen and option to view the Powershell script.
20. Click Install.
21. The install will tick over and when it has finished the server will be restarted.
The server will now reboot and the promotion is complete.