How to fix Windows 8 activation after clean install using an upgrade media

win8 clean install upgrade media

You probably heard that this time around Microsoft is letting people clean install Windows 8 using an upgrade installation media (e.g., DVD or USB drive). However the catch is that you need to have a previous valid version of Windows already installed in your PC to properly activate the operating system.

As the guys from Lifehacker pointed out, if you are using the “Windows 8 Upgrade Assistant”, you are all set. But if you had a legitimate previous version of Windows and you mistakenly formatted the hard drive, moved to a new drive (e.g., Solid State Drive) or if you installed one of the “Previews” or “Windows 8 Enterprise RTM” not knowing that these versions of the operating system cannot be upgraded to Windows 8, you cannot do the “Custom” install, even though you may still have the product key sticker on the side of the PC. You’ll be able to do the installation, but you get an error 0x8007007B or error 0xC004F061, saying that the product key can only be used to upgrade (“The Software Licensing Service determined that this specified product key can only be used for upgrading, not for clean installation”).

Now apparently there is a workaround that fixes Windows 8 activation problem and makes possible to perform a clean install of Windows 8 using the upgrade media without a previous version of Windows already installed in your PC.

How to fix Windows 8 activation

  1. Open Start.

  2. Search for regedit, and press Enter to launch the Registry Editor.

  3. Navigate through the following path:

    HKEY_LOCAL_MACHINE/Software/Microsoft/Windows/CurrentVersion/Setup/OOBE/
  4. Then double-click on the MediabootInstall key in the right pane.

  5. Change the value from 1 to 0.

  6. Exit the Windows Registry, use the Windows key + X keyboard shortcut to bring the Power User menu and press the letter A to open the Command Prompt as an administrator.

  7. Type the following command and press Enter:

    slmgr /rearm
  8. Restart your computer to complete the task.

Once you are back into the OS, try to run the Activation utility as you would normally do and you should be able to do so without any errors.

Warning: A few things to keep in mind:

  • Because this requires you to change the Windows’ registry, I would recommend you to create a restore point, or even a full backup wouldn’t be a bad idea.
  • Make absolutely sure you have a valid product key from the previous version of Windows that belongs to the PC you are upgrading to Windows 8.

I haven’t tried it myself, but many online articles are claiming a success with this method. If you happen to be in a situation where you have to use this method or if you already done it, let us know whether you were successful. 

Source GuidingTech via Lifehacker