I had a telephone (and Teamviewer) support session with Steinberg today and - more or less by a coincidence - we discovered together what caused the problem. A human error. And that human is of course me… 
What I did at the start of the installation process was changing the destination folder. I´ve done that on several other installations before and that has not caused any problems - until now…
So when the installation was made to the default folder - Tada! Everything works as it should.
Learning things the hard way… 