So I have been thinking about upgrading my Windows 10 Home Edition to the Pro version, but I always get to the point where it seems that I had to reinstall the entire SO and quit. After some investigating I have done it this way: - following this post on the microsoft site I use one of the default keys for Windows 10 Pro and went to Settings > Update & Security > Activation > Change the product key; - next, Windows will activate the Pro functionalities and asks to restart; - now you have the Pro version but it's not activated, so you have to buy a Windows Pro Key. I went to UR cdkeys and bought a key for less then €20; - and with the new key went to Change the product key and activated; - and it's done. Disclaimer : I have nothing to do with UR cdkeys so you can use any site to buy you cd key and your experience may vary from mine.