MegaBurn: I had the same problem. The GOG default install crashes on start up, and with the unofficial patch it quits with the error "GLW_StartOpenGL() - could not load OpenGL subsystem". The troubleshooting docs reference a safe mode short cut which doesn't exist (missing from installer?), deleting or editing the wolfconfig.cfg file which doesn't exist (game quits before creating it), and OpenGL stuff that seems obsolete (3dfx/Glade).
After wasting a few hours on troubleshooting - which GOG should have already documented in both an updated readme and support page - the following solution got it running.
Case (scenario): Fresh default install which crashes on startup -and- with the unofficial patch installed it quits with the "could not load OpenGL subsystem" error, -and- it did not create ~\Return to Castle Wolfenstein\Main\wolfconfig.cfg. -and- no other OpenGL related problems experienced on this Windows PC. Note, specs and driver versions are mostly irrelevant, if you can run other Id Tech OpenGL based games without problems then it fits with this case.
Theory (cause): Bad auto-config script, which can be bypassed using in-game config menu.
Solution (summary): Add some lines to autoexec.cfg to use software render to create the wolfconfig.cfg file, disable software render in autoexec.cfg, edit wolfconfig.cfg file to enable windowed mode (essentially safe mode), start game then use settings menu to adjust settings as needed including switch back to full screen.
Directions:
- Step 1: Open ~\Return to Castle Wolfenstein\Main\autoexec.cfg in notepad (or Notepad++), paste the following lines to the end (on new lines after "set devdll 1" ), and save the file. Closing the file is not necessary. Feel free to adjust the custom height and width to your desired resolution. Note, credit for this config goes to a thread Google found on the Steam forums, unfortunately for them they gave up without trying windowed mode to get it running (not my first run in with bad auto config on old games...).
set r_glIgnoreWicked3D "1"
set r_mode "-1"
set r_customheight "768"
set r_customwidth "1024"
set r_allowsoftwaregl "1"
- Step 2: Start the game. In my case, I received the same "GLW_StartOpenGL() - could not load OpenGL subsystem" error, but it may run in software mode with poor performance, in either case exit as soon as possible (forum comments indicate software mode is unstable, including hard lockups). Check for the ~\Return to Castle Wolfenstein\Main\wolfconfig.cfg file - if this file was NOT created then this solution has failed, start over or try something else.
- Step 3: Edit ~\Return to Castle Wolfenstein\Main\autoexec.cfg, delete the lines pasted in step 1 (so only "set devdll 1" remains), and save & close. Edit ~\Return to Castle Wolfenstein\Main\wolfconfig.cfg, find the line "seta r_fullscreen", change the "1" to a "0", and save & close. Note, further changes will probably be overwritten in step 4.
- Step 4: Start the game, at this point it should run fine in windowed mode (again, if not, you have some other problem). At the main menu (hit esc to skip the intro video), click "options", then click "system", and adjust the graphics settings to taste, maximum, including switch to full screen. Do NOT use the "set recommended" or "default", for me this causes the game to quit with the same "could not load OpenGL subsystem" error, but the game restarts fine, so I'm guessing it doesn't save those settings to the config file.
- Step 5: Restart the game and start the campaign to ensure its in good working order.
Note, in troubleshooting this there are references to starting in "safe mode" but that seems to be missing from the GOG installer, and I did not find a reference to command line switches for either "safe mode" or "windowed mode", any of which would have made this easier.
Hope that helps. Also hope GOG updates the readme file, Support page, and eventually the buggy auto config script.