How To Downgrade Windows 10
Long story short, I needed to downgrade from Windows 10 Pro to Windows 10 Home and as I discovered, it’s a bit of a tricky situation that requires editing the registry. If you want to downgrade from within Windows using the Media Creation Tool and not have to create a USB key, this is what you will have to do. In my situation, attempting to run the Media Creation Tool resulted in some error about not being able to upgrade (even though I was trying to do a fresh install). The following steps worked on my machine and should work on yours as well.