Microsoft Defender AV must be configured to perform a weekly scheduled scan.

This policy setting allows specifying 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 this setting is enabled, a scheduled scan will run at the frequency specified. If this setting is disabled or not configured, a scheduled scan will run at a default frequency.

Verify the policy value for Computer Configuration >> Administrative Templates >> Windows Components >> Microsoft Defender Antivirus >> Scan >> "Specify the day of the week to run a scheduled scan" is set to "Enabled" and anything other than "Never" is selected in the drop-down box.

Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Policies\Microsoft\Windows Defender\Scan

If the value "ScheduleDay" is "REG_DWORD = 0x8", this is a finding. Values of "0x0" through "0x7" are acceptable and not a finding.

Alternate Check (if Microsoft Intune applied this setting):

Navigate to "HKLM\Software\Policies\Microsoft\Windows Defender\Policy Manager".

If the value "ScheduleScanDay" is "REG_DWORD = 0x8", this is a finding. Values of "0x0" through "0x7" are acceptable and not a finding.

Set the policy value for Computer Configuration >> Administrative Templates >> Windows Components >> Microsoft Defender Antivirus >> Scan >> "Specify the day of the week to run a scheduled scan" to "Enabled " and select anything other than "Never" in the drop-down box.