Warning:
Do not run this process while performing other system-intensive processes, such as defragmenting your hard drive or scanning for viruses.
Do not run this process for multiple games at the same time.
Verify integrity of 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.
Once the process is completed, open the game again.
I hope this text and I helped you
Have a nice day!