On Windows Vista without service packs, WGA validation failure has a greater impact. In addition to persistent notification and the disabling of non-critical updates, WGA also disables Windows Aero, Windows Defender and Windows ReadyBoost. The user is given a grace period in which to then pass validation, after which most of the operating system is disabled and Windows reverts to reduced functionality mode. This behavior however has been removed in Service Pack 1 of Windows Vista in favor of prominent notices on systems believed unlicensed.