Lossless Scaling cannot process a game running in exclusive fullscreen mode. Launch your target game. Go to the display graphics menu. Change the display mode to or Borderless Windowed .
Note: Lossless Scaling requires Windows. This applies to Steam Decks running Windows dual-boot setups.
(v3.1.0):
Lock your game to 30, 40, or 60 FPS (use RivaTuner or in-game limiter).
Lossless Scaling Frame Gen 3.1 Just Solved Its BIGGEST Issue!