If your Steam games fail to load or crash on startup, it may be due to a file corruption in your game files,
To fix corrupted game files, you can have Steam validate the game’s cache on your system. Steam will examine the game’s files and will re-download the corrupted files from Steam’s servers if any problems are detected.
To validate a game’s cache, right click the game in your Steam library and select Properties at the bottom.
this will verify your game file is intact, and then attempt to download any files that need replacing.
For further assistance with the Steam Client, we recommend contacting Valve’s support team HERE.