Worklet: Set Windows Defender to do a Full Scan at Least Once a Week (or Never)

This particular worklet looks for any system set to never run a full scan and changes it to run on Wednesdays. You could obviously alter it to look for a different condition and set it how you wish. For example…

You could look for systems not set to do a full scan every day in the evaluation and change it to do so…
Evaluation: if ($Preferences.RemediationScheduleDay -ne 0)
Remediation: Set-MpPreference -RemediationScheduleDay 0

Or conversely, if you want Defender to never do a full scan…
Evaluation: if ($Preferences.RemediationScheduleDay -ne 8)
Remediation: Set-MpPreference -RemediationScheduleDay 8

The acceptable values for this parameter are:

  • 0: Everyday
  • 1: Sunday
  • 2: Monday
  • 3: Tuesday
  • 4: Wednesday
  • 5: Thursday
  • 6: Friday
  • 7: Saturday
  • 8: Never

Evaluation:

# Determine if full Defender scans are set to never run
$Preferences = Get-MpPreference
if ($Preferences.RemediationScheduleDay -eq 8)
    { exit 1 }
else
    { exit 0 }

Remediation:

# Set a full Defender scan to run on Wednesdays
Set-MpPreference -RemediationScheduleDay 4
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