Launch the command prompt as an administrator (Windows key & X –or CMD X if running on a Mac).
Type regedit and press enter.
Navigate to HKEY_LOCAL_MACHINE/Software/Microsoft/Windows/CurrentVersion/Setup/OOBE
Look for the item MediaBootInstall and set the status to 0
Close regedit and head back to the command prompt that should be still open.
Type slmgr /rearm and restart when prompted.