Please try the following:

  1. Exit Steam.
  2. Right-click on Steam icon.
  3. Left-click on "Run As Administrator".
  4. Right-click on the game in Steam Library. Click on "Properties".
  5. Select "Local files" tab and click on "Verify integrity of game cache files" button.
  6. Please wait, the process can take several minutes.
  7. If the issue persists, reboot your PC and try one more time from step 2.