To GOG Support (assuming you read this): I reported the problem to you not long ago.

There is still something wrong: The launch window appears twice before the game starts. Has launching either Nehrim or Oblivion (Steam) affected the change?

Settings have gone (they were there when I started writing this post), re-entering them in Launcher - Options ok, click 'Play', launcher window disappears, reappears, click 'Play' again, Oblivion starts as if nothing had happened. Nehrim runs (how can I check which Oblivion installation Nehrim uses? - all I see is that it uses the normal oblivion.ini in My Games\Oblivion). Update: What's going on here? Oblivion runs on Steam, but not on GOG. Has someone managed to play Oblivion on a Win 10 PC today? My OS is Win10 64 bit, by the way, and there has been a Windows update yesterday indeed. To all Oblivion players: Can you run Oblivion today? Oblivion task is not shown in the task manager. Launch window comes up, I click 'Play', launch window disappears, hourglass cursor is visible for a second, disappears - nothing.