User Account Control is a technology on Windows Vista and up that improves security on systems by limiting processes to standard user privileges until an administrator manually authorizes privilege elevation.
Tasks that require elevated privileges will trigger a UAC prompt.
Despite the improvement in security, UAC has been widely regarded as an annoyance in Windows Vista, asking every time an application requests elevation, without any way to whitelist applications. In Windows 7, UAC has four levels of configuration rather than two in Vista (on and off).
