I bought a new solid state drive, cloned the old one to the new using CloneDrive, removed the old drive and booted. Everything went well, but when I tried to start Unity I got this popup:
I am currently just toying around with the free version anyway, so this is no problem to me, but I guess it could be quite troublesome when someone would be in the middle of an actual project with the paid version.
It seems like replacing your hard drive invalidates your Unity license. What other changes to the PC hardware can cause this to happen?
I do not want to know how Unity detects hardware changes, I want to know which kind of hardware changes need to be avoided to prevent Unity from causing trouble which might lead to disruption of a project schedule.