Hey. New member here. I've tried 16, love it. It installed Windows 10 for my trial run. So I purchased Parallels 16. Now I want to upgrade from Windows 10 to 10 Pro. I have an un-used copy on disc with purchased sealed label. I entered this product key and it keeps coming up as invalid. Is my 10 Pro key really invalid or is there an issue with this in Parallels? Anyone come across this at all?