Paste these files directly into your main MW3 installation directory.
The most dreaded of these is the that appears when trying to join a multiplayer match or start a co-op session. This happens when the client files (the game you have) and the server files (or the pack you installed) are out of sync.
Method 1: Selecting the Language During Setup (Clean Install)
Most repacks use a Steam emulator (like Goldberg, Codex, or ALI213) to run the game offline.
Look for a configuration file named steam_api.ini , context.ini , or localization.txt . Right-click the file and open it with . Use Ctrl + F to search for the line reading Language= .
Method 3: Modifying the Registry (If Text Still Isn't Changing)