Have been running into a bug with Proton 8 and higher recently. Apparently it's a known issue. Proton 8 + certain pre-requisites + Nvidia drivers result in a no launch due to pre-requisites not being installed/updated.

The workaround is to switch to Proton 7.0-6 and let the pre-req install. Then after the game fails to launch, stop it, and switch back to 8 or experimental. Also for unknown reasons, if you have mangohud installed (even if you're not using it), you have to add mangohud=1 in the launch commands. If not, it simply will not launch.

I'd hoped Valve would have addressed this by now, but it's been going on since Baldurs Gate 3 officially released about a month ago.

This does not appear to impact AMD users, but I cannot confirm as I only have Nvidia cards.

    6 days later

    Interesting, I'm also seeing this issue with Proton 8 (also GE-Proton) plus another one where many games seem to freeze after a short while, continue in the background when you ALT+TAB or switch workspaces, but soon freeze again if you switch the focus back to them. Saw it with e.g. "Potion Craft", "Space Hulk: Deathwing", etc.
    Weirdly sometimes, but rarely, the game stops freezing after switching away from and back to the game. But I could only trigger this behaviour once or twice, and then never again. Switching to Proton 7 is the more consistent workaround.

    10 days later

    zmaint So thanks to this Reddit post I've found out that this is an issue with having "Force Composition Pipeline" enabled in nvidia-settings. Disabling that setting allows Proton 8 to work without any issues

        zmaint At least it fixes the freezing issues for me. But hopefully also helpful against the other problems.

            Shouldn't "Force Composition Pipeline" be disabled by default? Had just the problems with Steam trough the nVidia beta drivers last week. None of my games was launching. After de-installing them and reinstall the driver trough DoFlicky Driver Management I had no problems in launching my games again.

              Phiqu Shouldn't "Force Composition Pipeline" be disabled by default?

              Yes, it's disabled by default AFAIK

                12 days later

                Staudey Well I'm having the same issue on my laptop and it's all AMD 🙁