Scheduled Defender Scan Does Not Run

Quite a while ago I created a Scheduled Task to run a daily manual Defender Quick Scan. It worked fine until the recent Creator's Update/Defender Update (not sure which messed it).

I know some things changed with Defender and its path but I can't figure out what to change or how to get a scheduled Task created to run a Defender Scan. Since I have the Defender Scan as part of maintenance disabled (I did not need the duplication of effort) Defender doesn't scan my computer. Why does MS always have to mess things up. If anyone knows how to create a Task to run a Defender scan please let me know.

Brink said:

Hello bru, :)

You might see if the method used in the tutorial may be able to help any.

Schedule Scan in Windows Defender Antivirus in Windows 10 Security System Tutorials

Used that to create the task a while ago. And like I said it worked fine until the dual updates. Now it doesn't.

I'm curious if anyone who did the same (created a task for a scheduled Defender scan) is or isn't having the same issue? I've heard others report it on another forum.

@bru
Running Ver 1709.

I have posted here before stating that automatic maintenace does not run on my PC. Never has.
So I created a manual scan under Ver 1607.. It continues to work ok.

Jeddie said:

@bru
Running Ver 1709.

I have posted here before stating that automatic maintenace does not run on my PC. Never has.
So I created a manual scan under Ver 1607.. It continues to work ok.

On four different PCs the manual scan I created that previously worked fine does not in v1709. Or at least I think it doesn't. It may work sporadically but even that is not consistent across devices. One just had the red triangle over the Defender icon since a scan had not been run in a while. And I do have periodic scheduled maintenance scans enabled as it seems its impossible to disable them anymore.

Did you change something in the task for v1709? I'm guessing no. Can you post the "Actions" you are using in the task? Also, if you check your "Last Run Result" what does it say? I have verified that it says "Incorrect Function" but have been told a scan still runs. If true, for me it is not registering as a run scan in either the old Defender GUI or the new one.

No I have not changed anything in the task.
The Action I have in my scheduled task including the quotation marks = "C:\Program files\Windows Defender\\MpCmdrun.exe" Scan - Schedule job
The job is shown as; 0x0 The operation has completed successfully.

Just to be clear this is found in Task Schedule > Task Schedule Library > microsoft > windows > windows defender.

My default WD task returns 0x0 sometimes and 0x2 sometimes, which I think is normal if it tried to run and the PC wasn't idle. I even unchecked all the idle boxes, but doesn't seem to matter.

I was just looking at the default WD task and this seems new for the Program (Arguments are the same IIRC).
Program > C:\ProgramData\Microsoft\Windows Defender\platform\4.12.17007.17123-0\MpCmdRun.exe
Arguments > Scan -ScheduleJob -ScanTrigger 55
Runs under System Account

I also added my ow WD task that runs every day at 6:00AM and always completes successful with 0x0.
Program > "C:\Program Files\Windows Defender\MpCmdRun.exe"
Arguments > -SignatureUpdateAndQuickScan
Runs under System Account

Note: When I first setup my WD daily task (before 1709 and running under the System Account) it wouldn't complete successful and I want to say it returned the "incorrect function", but I just don't remember. I had to use my Local Account and I had to add my Local Account to Windows Credentials > Generic Credentials. I actually just switched it back to System Account a couple days ago, to see if it would complete successful and if not, what return code it gave. Thought maybe I could verify that "illegal function", but no luck ... it completed successful.

Jeddie said:

No I have not changed anything in the task.
The Action I have in my scheduled task including the quotation marks = "C:\Program files\Windows Defender\\MpCmdrun.exe" Scan - Schedule job
The job is shown as; 0x0 The operation has completed successfully.

Just to be clear this is found in Task Schedule > Task Schedule Library > microsoft > windows > windows defender.

That is the built in maintenance scan. You apparently modified the built in task. I am taking about creating a new task to run a scheduled scan.

Eagle51 said:

My default WD task returns 0x0 sometimes and 0x2 sometimes, which I think is normal if it tried to run and the PC wasn't idle. I even unchecked all the idle boxes, but doesn't seem to matter.

I was just looking at the default WD task and this seems new for the Program (Arguments are the same IIRC).
Program > C:\ProgramData\Microsoft\Windows Defender\platform\4.12.17007.17123-0\MpCmdRun.exe
Arguments > Scan -ScheduleJob -ScanTrigger 55
Runs under System Account

I also added my ow WD task that runs every day at 6:00AM and always completes successful with 0x0.
Program > "C:\Program Files\Windows Defender\MpCmdRun.exe"
Arguments > -SignatureUpdateAndQuickScan
Runs under System Account

Note: When I first setup my WD daily task (before 1709 and running under the System Account) it wouldn't complete successful and I want to say it returned the "incorrect function", but I just don't remember. I had to use my Local Account and I had to add my Local Account to Windows Credentials > Generic Credentials. I actually just switched it back to System Account a couple days ago, to see if it would complete successful and if not, what return code it gave. Thought maybe I could verify that "illegal function", but no luck ... it completed successful.

The action for my created scheduled task to run a Quick Scan is a bit different, has to do with UI iirc from when I set it up. Interestingly two computers yesterday ran the scheduled scan and gave me the notification in the action center, which has not been occurring since the 1709 update. Doesn't look like anything changed in Defender in terms of another update so not sure why.

bru said:

That is the built in maintenance scan. You apparently modified the built in task. I am taking about creating a new task to run a scheduled scan.

No Bru - I am referring to a Task I created. As I sadi the automatic (built- in) scan does not work for me. Thats why I created my own task.

Jeddie said:

No Bru - I am referring to a Task I created. As I sadi the automatic (built- in) scan does not work for me. Thats why I created my own task.

Interestingly my scheduled scan has worked the last two days. Nothing changed on my end so I wonder if something happened behind the scenes.