'Specify the day of the week to run a scheduled scan' for ScheduleDay to every_day This policy setting allows you to specify the day of the week on which to perform a scheduled scan. The scan can also be configured to run every day or to never run at all. This setting can be configured with the following ordinal number values: (0x0) Every Day (0x1) Sunday (0x2) Monday (0x3) Tuesday (0x4) Wednesday (0x5) Thursday (0x6) Friday (0x7) Saturday (0x8) Never (default) If you enable this setting, a scheduled scan will run at the frequency specified. If you disable or do not configure this setting, a scheduled scan will run at a default frequency. Counter Measure: Configure this setting depending on your organization's requirements. Potential Impact: Scheduled scans can impact performance.

(1) GPO: Computer Configuration\Administrative Templates\Windows Components\Windows Defender\Scan\Specify the day of the week to run a scheduled scan (2) REG: HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows Defender\Scan\ScheduleDay