Reinstalling upgraded Windows

reinstalling a license of an upgraded Windows (from 7 -> 10) for example may be a real pain since you have to reinstall the old version and upgrade it to the upgraded one.

I found this thread on the Microsoft support forum that explains how to install directly the upgraded OS and validate your valid license correctly.

from MS support forum thread

The workaround for this, while probably not officially supported for obvious reasons (they want more money), is to change a registry key.

This was posted for Windows 7 update keys doing the same thing on a forum (though I had an updated version AND did a clean install MULTIPLE times without having to do this) but worked without an issue on my laptop running Windows 8 regardless.

  1. Run the registry editor (Regedit)
  2. Find the following key:
  3. Change the value for ‘MediaBootInstall‘ from 1 to 0.
  4. Open an elevated command prompt (run as admin)
  5. Run the following command:
    slmgr -rearm
  6. Reboot

If you already entered your key, check the activation: for me, it was already activated and I needed to do nothing more. If not, type in activate windows and type in the key; it should work.

Also, do yourself a favor and export this key from Regedit and save it somewhere if you ever are required to do another clean install. I know I did.