This policy setting allows you to manage whether a check for new virus and spyware definitions will occur immediately after service startup. If you enable this setting, a check for new definitions will occur after service startup. If you disable this setting or do not configure this setting, a check for new definitions will not occur after service startup. Fix: (1) GPO: Computer Configuration\Administrative Templates\Windows Components\Windows Defender\Signature Updates!Check for the latest virus and spyware definitions on startup (2) REG: HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows Defender\Signature Updates!UpdateOnStartUp