Updating KMS server for Windows 2012 R2 and Windows 8.1

Windows 2012 R2 and Windows 8.1 were released today.  If you are an enterprise customer running a KMS server, you'll probably be looking add your new key.  Upon doing so, you will quickly receive an error message telling you that your new KMS key is invalid... because it is.

You could install a Windows 2012 R2 server and replace your existing KMS server.  That would be great, but that's not a great solution for existing KMS customers.  Instead, Microsoft has provided KB2885698 that will update KMS so that it accepts the new keys.

You can download it here: KB2885698  The down side is that this update does require a reboot.

Once you have applied the update, open an elevated command prompt and issue the following commands. NOTE: If the title of the command prompt doesn't have the word Administrator in it, then you aren't in an administrative command prompt.

Install the product key:
slmgr.vbs /ipk

Activate the product key:
slmgr.vbs /ato



Thats it.