- Launch Steam
- From the 'Library' section, right-click on the game and select 'Properties' from the menu.
- Select the 'Local Files' tab and click the 'Verify Integrity of Game Files' button.
- Steam will verify the game's files - this process may take several minutes. This will always download a number of files even if you've just verified.
- Once the process is completed, close the windows then launch the game.
Edited by Neil Brock