For example, a file named zone/english/code_post_gfx.ff contains essential global data, while files like zone/english/mp_rust.ff contain the multiplayer map data for Rust.
Instead of risking your PC's security with random downloads, you should use the official launcher tools to automatically scan, download, and replace missing zone files. Method 1: Verify Game Files on Steam (PC) Cod Mw3 Zone Files Download
Zone errors are frequently caused by bad sectors on your Hard Drive (HDD) or Solid State Drive (SSD). For example, a file named zone/english/code_post_gfx