Of Duty World At War Filesyscheck.cfg Error — Call

This will flag you as "modified" for pure vanilla multiplayer, but since the official matchmaking is mostly dead or infested with hackers, you should be using community clients like Plutonium anyway.

The error is notorious for appearing if you use:

filesyscheck.cfg not found

If the directory path is correct but the game still won't boot, the issue might be related to outdated system drivers or DirectX.