j_c: thanks - that's what I was looking for!
Profile Hauptbenutzer = Power User, Benutzer = Limited
The meaning of the words is a bit different: German "Benutzer" is translated "User", which sounds quite normal, while English "Limited" sounds a bit more restricted...
So what I said was for a user in group Limited: it will have problems to work with XY, if you don't allow "Update" for Group Limited on XY install-directory.
And as I said: this is an XY-issue, as it "misuses" (sorry, Don) the program directory for user data.
Just to ensure: I'm not talking about what files I can handle (read, copy, delete, ...) in XY - this is reglemented by authorizations of user profile, but about the ability just to use XY in a common way, if you are are "Restricted" user! (While that user has no problems to use and "configure" Win Explorer...

)
Hey Don, what do you think of an airbag in your car? I don't have one, and never had an accident!
I surf a lot, I always surf as admin (!), I never used any virus soft, I never got any virus ever!
Again: every server can be hacked to be infective, and from time to time every browser can be infected when accessing an infected server. Some time ago even the IP-stack of your PC could be infectible by some virus.
Even if you drive your car quite safely you should have airbag
and seatbelt
and crush zone
and head-rest
and ... - does anybody think, it's wrong?
And if you use your browser quite safely you should have ... - or what do you think? I for my part don't want to trust on my good luck for that! I don't want to at home, and I'm not allowed to at work - for good reason!
Quite a lot of stuff - now I'll wait what others say
