Compatibility Report

• Name of the game with compatibility issues: Call Of Duty 4
• Steam AppID of the game: 7940

System Information

• Proton version:4.2-9

The COD4X mod does not work in Proton but does work in Wine. I installed Call Of Duty 4 in Steam via Proton and installed the COD4X Mod, I installed Steam windows client in WINE, then installed Call Of Duty 4 in Steam Wine and installed the COD4X mod. When I joined a server in Wine it will let me join, in the Proton it will crash.

I believe this is because when Steam launches a game using Proton it does it differently than WINE will launch a EXE file and therefore issue will occur. I could be wrong but this is my understanding of the issue.

Here is the proton log file
https://privatebin.net/?fa2ec3d6412f9edc#4u1y3EXLQJr6KgAnezyYkr5bdo4XJ7GLH5uyVbeo3LV1

You can download the COD4X mod here in the link below, You will want to download the Windows Client, not the Windows or Linux Server.
https://cod4x.me/

NOTE: To get COD4X installed in Proton (Not WINE) you will need to take an few additional steps. You need to create a symbolic link in the proton prefix in order for COD4X to work. If you do not do this, once you install COD4X the game will not launch and you will get an error message.

1. Open the terminal and enter the following command. REPLACE "USERNAME" WITH YOUR USER NAME.

sudo ln -s "/home/USERNAME/.steam/steam/steamapps/compatdata/7940/pfx/drive_c/users/steamuser" "/home/USERNAME/.steam/steam/steamapps/compatdata/7940/pfx/drive_c/"

1. Rename the steamuser symbolic link in your
   /home/USERNAME/.steam/steam/steamapps/compatdata/7940/pfx/drive_c/ to your Linux username.

MAKE SURE YOU DO THE PREVIOUS STEP BEFORE YOU DO THE NEXT STEP OR ELSE YOU WILL DAMAGE YOUR PROTON PREFIX

1. Copy the renamed symbolic link and paste it into your /home/USERNAME/.steam/steam/steamapps/compatdata/7940/pfx/drive_c/users/ folder