To verify individual games on Steam do the following: While that is useful if you only need to verify one game or maybe two games, it is not really a solution if you need to verify all games you have installed on your system.
It simply takes to long and requires too much attention to be practicable.
Before playing a game, you may want to verify its cache – in other words, check to make sure all its files are present on your system and aren’t corrupted.
Game gets stuck on loading screen: This happens because of missing / corrupt files.
Often it's because of your Anti-virus program so disable it.
Verifying the cache files of the game can help to ensure that the installation of a game is up-to-date and if necessary repair any bad or corrupted game data. Steam will verify the game's files - this process may take several minutes. Once the process is completed, the Check Window will automatically exit.
To verify the cache files of your game please follow the steps below; 1. 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...
If its different in any way it replaces or adds on any files.