Feels like there is mouse acceleration in Quake 2. Is there a way to turn this off?

Hmm, not sure. As always, I suggest using a source port like KMQuake 2 or Yamagi. That provides a new engine for the graphics, sound, and controls. You might like that more.

I tried KMQuake 2 but didn't like the updated graphics. I'll fall back to it though if there is no other option.

If this don't fix it, it gotta be something else right?
I've turned it off both through the SteelSeries software and with the MarkC fix. No mouse acceleration in Windows and it don't actually feel like it's any acceleration in Q2 either. It's more like the mouse can't read the surface correctly. But it's the same problem with my other mousepad and there is no problem in any other game.

I somehow managed to play through Q2 with this annoying mouse "skipping" a while ago. But I'm not touching the mission packs until I've fixed it. Trying to find a way.

The acceleration problem is not as the mouse skip problem... check all hdd/ssd status with crystaldiskinfo and check if is already enabled Ultra DMA mode

If you use the 3.20 version of Quake II (without source ports), try to install unofficial 3.24 version and disable Mouse acceleration

I ordered me a new mousepad. It's a black SteelSeeries pad. It's much better now.
So it was the mousepad after all. But on the other hand, the culprit also has to be that the game uses software mode as there's no problem in other games.

So it wasn't an acceleration problem.