Thank you for your kind kind words @adsii1970, it means a lot to me.
I still don't get it. Five times today I spent substantial time and a lot of energy with this issue (interrupted by other issues from other customers). Three hours, out of nine of my work day. Poorly engineered software (Terminal Server, anyone?). An incompetent and ignorant "support engineer", twice. And yes, that particular "support engineer" didn't understand any of the very basics (Terminal Server, Roaming Profiles, Folder redirection, non-persistent environment, or that users don't have admin rights - just: nothing), nor could speak either German or English in an understandable manner. An unhappy customer. Totally in his rights, of course, but his complaints aimed at me? Then, to whom he could complain? His 3rd party software vendor? They only offer a phone waiting queue where you can listen to some music, for minutes, if not hours. Finally solved the core issue myself. Lastly, an older guy from the vendor's company ironed out the final kinks (like: to be able to import the data from the old version to the new one, the old one needed to be upgraded). Then the icing of the cake: my boss telling me "that's just your job".
Something must be wrong with me, having issues and taking offense here.
Modern times, I guess.
If there is one thing we humans do excel in, amongst and foremost of every other creature, it is to make life for every living being on this planet as miserable as possible.
Maybe is this what being "human" means.