Wait for the small update to download, then switch it back to English.

Instead of searching for third-party download links—which are often unsafe or contain malware—use the official verification tools provided by game launchers to repair the file. Open your Steam Library and right-click on Call of Duty: Modern Warfare II . Select Properties > Installed Files .

Why does the game keep telling me ERROR: could not find zone: 'ui.ff?

Instead of searching for a manual download link, which can be risky, use these official methods to restore the file: