I see purple checkerboards, weapon or world models are missing, or experience crashes while playing a game - how can I verify that my game files are installed correctly?
1. Restart your computer and launch Steam
2. From the Library section, right-click on the game and select Properties from the menu.
3. Select the Local files tab and click the Verify integrity of game files... button.
4. Steam will verify the game's files - this process may take several minutes.
5. Once the process is completed, the window will automatically exit, and any files found to be damaged will be re-downloaded by Steam.
More information is available on the Steam support site.