No, that's not my problem. I did also get this windows with buttons at the buttom I could not see, but I just hit "Enter" and could start the game. When the game was started, I hit the "new game" button and that is where I got stuck. I see a fullscreen window with label "loading" in the right lower corner and titled with Divinity Original Sin, so it seems to be the normal loading screen. But loading seems to never end for me.
