[Sabine Klare]

That's very good, that the Cloud Account doesn't care, what user account I am using on my machine. And although the file path of my username-folder has still the wrong name, I had edited the PC-Name to the right name successfully (in the service shop they had edited the username).

Fortunately my files are not in the username-folder on C, they are in another folder on D now.

It can happen, that the wrong username is set up by installing / reinstalling Windows...