I sometime have to change the Windows 8.1 License Key. Normally you should not have to do this after you have install Windows, but I sometimes get stuck with doing a rush install before the volume licensing keys have arrived. They have been purchased, but the person with the Microsoft Volume Licensing Center login is gone for the day. The client has made me an admin, but didn’t realize that it takes time for that to provision. So in my haste, I installed a trial version of Windows 8.1 Pro.

A month goes by and the Activate Me please screens show up and of course I try to click Activate. Windows Activation isn’t having any of that. I try to put in the new volume licensing key, but Windows won’t accept it. Or will it…

To change a Windows 8.1 or 8.0 License Key, we need to do some some unholy casting. This will allow us to use a Retail, Volume License, OEM, OEI, or a OUA key.

Run cmd.exe as an Administrator and then do the following:

1. To change the Windows key:

slmgr.vbs -ipk YOUR_KEY_HERE

2. To activate windows after changing the key:

slmgr.vbs -ato