The WSUS Client Diagnostics Tool is a diagnostic tool that helps to determine the causes of communication problems between client machines and the server. The application works by testing the transmission by performing four main tests - verification of machine status, comparison of AU settings and checking proxy settings, during which the program verifies the efficiency of Automatic Update and BITS services, wuaueng.dll file version, in order to determine the available AU version and WUServer and WUStatus values.