WGCheck is a program designed to diagnose and repair games published by Wargaming. Its interface is straightforward and easy to understand for a player who does not know much about inner structure of the game - open-select-fix.
You can find official manual for WGCheck in Customer Support Center.
Upon launcing the program you will see basic data about your computer, including CPU and GPU sensors data.
At the time of writing, the current WGCheck version is 188.8.131.52.
To start working with the utility, you should click "Add game" button. Explorer prompt will appear where you should select the game executable. WGCheck detect client type and region automatically when it's possible. The screenshot below shows WGCheck verifying World of Tanks client for RU region.
Even the basic client verification might take much time. It's highly recommended to wait till the process ends and close resource demandng programs.
In my case, basic verification took about ten minutes. Due to the fact that I make mods, it's not surprising to see mods and external files in my game client.
WGCheck saves its report automatically in game directory named WoT_report.wgc, but the beginning of the name may vary depending on the game chosen to verify. Report you made will be useful when you are going to fill a bug report on Wargaming's bug tracker, helping Customer Support Center employees to figure out what happened to your game or if you want your friend to help fixing your game instance. Also you must attach WGCheck report if you want to describe the bug happened on World of Tanks Common Test server, otherwise your topic will be closed for "insufficient info" reason.