So this has occured for me for a while now since I updated to Windows 10. When I start Unity 5, I get the licence error message and I can’t re-activate or anything. Everything worked fine before I upgraded to W10. I have tried to re-install Unity and even creating a new account to make it work but even that fails.
When you searched and tried the described solutions did that not work?
Thanks alot! It worked when I removed the Unity folder in ProgramData.