This is most likely due to the game encountering an incomplete install or update.
To combat this, please verify your Steam cache. This can be done by following the instructions below:
Verify Game Cache:
- Load 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 Cache' 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 the game.
- Once the process is completed, the Check Window will automatically exit.
- We recommend verifying your cache twice to make sure all files are fully downloaded.