Many antivirus programs flag iw4sp.exe as a "false positive" because of how older Activision games manage memory. Check your antivirus "Quarantine" folder and restore the file if it's there.
If you own the game on and the file is missing or corrupted, do not download a replacement. Let Steam regenerate it for you: Open your Steam Library . Right-click on Call of Duty: Modern Warfare 2 (2009) . Select Properties > Installed Files . Click Verify integrity of game files . call of duty modern warfare 2 iw4sp.exe download
Using modified executables while connected to Steam can occasionally trigger VAC (Valve Anti-Cheat) flags. How to Fix a Missing iw4sp.exe Safely Many antivirus programs flag iw4sp
These files are often bundled with trojans or miners. Let Steam regenerate it for you: Open your Steam Library
If you search for "iw4sp.exe download," you will find dozens of "DLL-fixer" or "abandonware" sites offering the file.
If the .exe version doesn't match your game's patch version (e.g., v1.2.208), the game will crash on startup anyway.