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.
Policy path:
Windows Components\Windows Defender\Signature Updates
Scope:
Machine
Supported on:
At least Windows Server 2012 Windows 8 or Windows RT
Registry settings:
HKLM\Software\Policies\Microsoft\Windows Defender\Signature Updates!UpdateOnStartUp
Filename:
WindowsDefender.admx