I've just bought a genuine Microsoft Windows 8.1 Pro 64-Bit Full Version DVD with COA and Key

I'm installing the software on a blank formatted hard drive, but when it's finished its only installed Windows 8.1 Core (Standard).

Windows activates fine, but when I try and change the key to Pro it says the key isn't valid.

What am I doing wrong.




  • 1
    Where'd you buy it from? – New-To-IT Jan 28 '15 at 21:07
  • 1
    Are you sure the key is genuine Pro... sounds a bit suspect to me that the key you have for Pro is returning as invalid. – Kinnectus Jan 28 '15 at 21:09
  • Bought it from bt business direct – John Moore Jan 28 '15 at 21:10
  • 2
    Return it all and get them to send you a confirmed Pro key. – Kinnectus Jan 28 '15 at 21:12
  • @JohnMoore - Post the configuration file from the disk that determines what the installer will see when it installs. – Ramhound Jan 28 '15 at 21:13

If you have an OEM Windows 8 Core edition preinstalled on your device, the OEM key is stored in the UEFI. If the setup detects such an key it uses this OEM key.

You should add a ei.cfg with this content:



to the sources folder on the dvd. Now Windows allows you to select which edition you want to install.


Ive created a WIN 8.1 pro iso usb disk using the microsoft creation tool.

The key works fine and activated as Pro and genuine.

Anyway, sorted now. Thanks for the pointers.

Thanks magicandri, the pc did come with 8.1 standard, so i get what u are saying. So thats why it may not have asked for the key during the first installation?


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