(Windows 11) Task Scheduler triggers automatically delete themselves after some time

Question

I'm trying to configure Windows 11's Windows Defender to only run itself at midnight each day, and at no other time. I've tried going into Task Scheduler and setting a trigger for each of the four sub-tasks to do so, and for the short time the triggers survive they do function correctly, but after around a week the tasks seem to auto-delete and recreate themselves and the processes revert to their original seemingly-random timings, which is a problem because Windows Defender Verification seems to be causing lag spikes in programs when it runs and I want to be able to control its run times. (Additionally, after resetting themselves the "Last Run Time" column is set to exactly 12:00 AM on November 30, 1999. They are not listed as having an author until I exit the "Properties" window.)

I've run Malwarebytes recently, although I don't know how that could possibly affect anything. (It's happened again days after my last MWB scan, so I doubt that's it.) I've scanned, both with Windows Defender and Malwarebytes, for malware. I have Process Lasso downloaded to block my games from entering Efficiency mode, so if that's causing a problem let me know.

Device name HP

Processor AMD Ryzen 5 7520U with Radeon Graphics 2.80 GHz

Installed RAM 16.0 GB (15.2 GB usable)

Device ID B0CF3B13-6D11-4CFD-A028-1B2868A83BC6

Product ID 00342-22175-81927-AAOEM

System type 64-bit operating system, x64-based processor

Pen and touch No pen or touch input is available for this display

Answer 1

It's probably a self-protection mechanism that is built into the OS to prevent users from accidentally (intentionally!) preventing needed Defender tasks from executing.

I have Win 11 Home and I don't see any way to manage those tasks.

Since you commented "for the short time the triggers survive they do function correctly", then you could try using your own scheduled task to execute a Powershell script which would update the triggers in the Defender tasks. Maybe schedule your task to run daily.

I would caution you that this is a "use at your own risk" situation. I don't know if there any side effects to changing the trigger time.

I did test the script and updated my tasks. I'm going to monitor them to see what happens. I don't know if the tasks will execute at the "random time" in addition to my trigger time.

After the triggers get reset, I'll just leave them as the default.

$DefenderTasks = Get-ScheduledTask | Where-Object -Property TaskPath -Like "*windows defender*"
foreach ($task in $DefenderTasks) {
    $tr = New-ScheduledTaskTrigger -Daily -At 12:01am
    Set-ScheduledTask -TaskPath $task.TaskPath -TaskName $task.TaskName -Trigger $tr
}