I don't have this title on Steam, so can't check it myself - @Houtworm - can you try using the following workaround to run this game?

Use following launch options:
NVIDIA proprietary drivers users: __GL_ExtensionStringVersion=17700 %command%
AMD/Intel: MESA_EXTENSION_MAX_YEAR=2003 %command%

BTW, spcr has report, that #831 affects this game as well.

@dreamer No that did not fix it, it actually stopped the game from launching at all, i did not see the green terminal thingy and Multiplayer also stopped working.

Thnx for the input Though :)

Edit, I have a GTX 1080, with NVIDIA 396.54 Drivers if that is any help i have tried this launch option
__GL_ExtensionStringVersion=17700 %command%

I have seen this behavior as well on my AMD Radeon HD 8970m+Intel HD 4000 (muxless setup) using Mesa 18.3.0, so at least we may be able to rule out driver issues.

I only have access to the game as sold by GOG, that version absolutely requires MESA_EXTENSION_MAX_YEAR=2003 to start.

If it still crashes you can start the game with "+set logfile 3" and it should write a log called rtcwconsole.log. Experimenting with ESYNC turned off might be worth a try too.

Log files from Wine would be useful too.

The MESA_EXTENSION_MAX_YEAR=2003 works for my system at least.
Here's the log file anyway when it crashes:
rtcwconsole.log
And, for what it's worth, when it succeeds with the MESA_EXTENSION_MAX_YEAR=2003:
rtcwconsole.log

It's just not finding some extensions without that variable set.
I don't know if it will, but I hope this helps.

I've found that if you add the unofficial 1.4b patch from http://www.markshan.com/knightmare/ the workaround is no longer necessary, the version installed by Steam is version 1.22.

@dreamer Your fix just helped me to play the game on my machine. Thank you.

System info: https://gist.github.com/jgacas/64704de0370633b265b2970b97ec7d35

I'm a Nvidia user and as said earlier in this discussion, the game only launches if I use this option at launch:
__GL_ExtensionStringVersion=17700 %command%
Star Wars Jedi Knight II outcast needs the same workaround #1732
If Steamplay integrates this workaround, the game could be whitelisted.
After that you could even set the game resolution to 1280x1080 for a 1920x1080 screen without instability and for a better gameplay experience.

Hello. With Proton 3.16-7, you can now use the PROTON_OLD_GL_STRING runtime option instead of the Mesa- or Nvidia-specific environment variables.

Just played this game 30 mn with Steam controller, nothing to report, ok for whitelisting.

Played the first few levels, and it was pretty much flawless. I think it's ok for whitelisting.

It might be worth noting here that if you're like me and try to force these older games into modern resolutions (1920x1080 in my case) you will encounter a crash after beating the third level, but this is the game itself not Proton.

Whitelist Request

• Name of the game to be whitelisted: Return to Castle Wolfenstein
• Steam AppID of the game: 9010

System Information

• GPU: AMD Radeon RX 580
• Driver/LLVM version: Mesa 20.0.7
• Distro version: Arch Linux
• Link to full system information report as Gist:
• Proton version: 5.0-7

I confirm:

• [X] that pressing the Play button in the Steam client is sufficient.
• [ ] that runtime config options are necessary to run the game.
• [ ] that no workarounds other than PROTON_* env variables are necessary.

Issues

• [X] I haven't experienced any issues.
• [ ] There are no issues left open for this game.
• [X] Although I consider the gaming experience equal to Windows there are remaining issues:

Played the first Level for 15 Minutes. No Issues.

It consistently crashes at the end of the TRAM level.