Ui.ff File Download ((install)) -

Click on the (or Local Files ) tab on the left menu. Click the Verify integrity of game files button.

Which (or software) is throwing the error?

.../Steam/steamapps/common/Call of Duty Modern Warfare Remastered/zone/

Instead of forcing your system to read thousands of loose, individual image and text files during a match loading screen, the engine packages them into massive .ff blocks.

The file is a specialized data container known as a "Fast File" used primarily by the Call of Duty (CoD) video game franchise. It is designed to store user interface assets, such as menus, buttons, icons, and fonts, which the game engine loads quickly during startup or gameplay. Core Technical Details