This policy setting allows you to manage whether a check for new virus and spyware definitions will occur before running a scan. This setting applies to scheduled scans as well as the command line "mpcmdrun -SigUpdate" but it has no effect on scans initiated manually from the user interface.If you enable this setting a check for new definitions will occur before running a scan.If you disable this setting or do not configure this setting the scan will start using the existing definitions.
Policy path:
Windows Components\Windows Defender\Scan
Scope:
Machine
Supported on:
At least Windows Vista
Registry settings:
HKLM\Software\Policies\Microsoft\Windows Defender\Scan!CheckForSignaturesBeforeRunningScan
Filename:
WindowsDefender.admx