Windows 10: Defender not Running Regular Scan

I assume you have the Anniversary Update? Something in it broke the functionality of Defender related scheduled tasks. I am having the exact same problem.

 

Yeah I have the AU update. It seems to work for everyone at the posts I linked but must have been before the AU update came around. I hope someone can work the problem out.

 

Does anyone know what the default scan schedule is for Windows defender?

 

Yep - I've got Ver 1607. There is something definitely not working.

Defender did do a scan today at 5.51pm, but, not my scheduled scan. I suspect this scan is part of Automatic Maintenance.
My Scheduled scan is for 8:00:56pm. The log appears to say it ran. Although it says it started and finished at the same time?




But when I look at the top of scheduler it is showing the same (0x2) error?




And looking at Defender GUI, it shows the last scan as 5.51pm?




Are there any experts out there who can hopefully advise on this? If its a Microsoft solution then I'll have to accept it (or get another AV)
I give up.

 

I haven't tried creating any manual schedules for scans just definition updates which is having a similar problem.

Does anyone know how often Defender scans with Automatic Maintenance?

 

Take a look at simrick's post on page 1. Set up a scheduled scan using his parameters.

I believe the Actions needed have changed. I was able to partially resolve my issue. I can get the definitions to update by using "%ProgramFiles%\Windows Defender\MpCmdRun.exe" -SignatureUpdate. Previously it has been "C\ProgramFiles\Windows Defender\MpCmdRun.exe" -SignatureUpdate.

I am still working on the scheduled Quick Scan. Also, if you get your scheduled scan to run you should disable the Quick Scan that is part of Automatic Maintenance. That is found in the Scheduler Library>Microsoft>Windows Defender>Windows Defender Scheduled Scan

 

Sounds good but I have a bigger problem now. I set my ethernet connection to metered in the registry following instructions from a post here at tenforums. I decided to return to a non metered connection for testing purposes but Windows update is not auto updating or installing defender definition updates as it should throwing error 0x80070643.

 

My scheduled Quick Scan did not run today. Last run result shows 0x2. The Windows Defender program does not show the scan ran under Scan Details as simrick reported. I am certain the task is scheduled correct.

The scheduled Quick Scan ran reliably before the AU but does not run now. Not sure what else to do other than hope MS fixes whatever the AU broke.

 

Could you use a 3rd party AV instead? That's what I think I might do.

 

You've got Defender doing manual scheduled definition updates now right? Why do you want to schedule scans? It looks as though it does an auto quick scan once daily.

 

Having up to date definitions is important, but a periodic scan will ensure the system is clean. MS agrees and included a Quick Scan as part of Automatic Maintenance. Problem is, in order for the Quick Scan that is part of Automatic Maintenance to run consistently, several things have to occur: The computer needs to be idle long enough for the scan to start. If the computer is set to sleep after 10-20 minutes that won't allow enough idle time for the scan to initiate. Assuming the computer is idle long enough for the scan to start, any activity on the computer will terminate the scan. And I mean anything. Even just moving the mouse will terminate the scan.

I was able to get the Auto Maintenance QS to run by delaying sleep for 30 minutes and making sure I didn't touch the computer. But those are some serious limitations for how I (and I suspect many) use my computer. So I set a scheduled task to run the Quick Scan. By setting specific conditions the scan will run to completion without terminating at a moments notice like the Auto Maintenance scan. I then disabled the Auto Maintenance Quick Scan since it would still try to run even though my scheduled scan had already occurred. The scheduled scan worked fine, until the AU. The AU somehow broke scheduled tasks related to Defender. It broke my scheduled task for definition updates, but I was able to resolve that as I previously posted. I have not been able to resolve the scheduled scan not running. At least not yet.

 

Fair enough, but couldn't you do this with a 3rd party AV? Apparently WD doesn't rank very high: Best Free PC Antivirus Software 2016 - Tom's Guide

 

Yes of course I could use a third party AV. Third party AVs tend to hog resources. The free versions have nag screens that appear often and some leave behind lots of remnants when removed. I have used MSE and WD for many years without issue. I do realize they don't rank as high as others but I do use MBAM as an adjunct and rarely have had problems.

WD meets my needs and I'd like to still use it, but as I want by scheduling it to run on my terms. Apparently MS doesn't want that to occur.

 

This issue (scheduled Defender Quick Scan) continues to perplex.

I am on my computer exactly when the scheduled scan should start. I see no evidence of it running via the icon in the notification area (no spinning blue wheel). However, when I opened Defender lo and behold a scan is running. Once Defender was opened the blue wheel appears on the icon in the notification area. The scan completed and shows in "Scan details: Last scan". In Task Scheduler the status shows "The operation completed successfully (0x0)". So that begs the question, is a scan really running if there is no evidence of it running? If I had not opened the program would the scan show as completed? Based on previous days I would say no, or maybe. Previously Task Scheduler always showed "(0x2)". This may go along with what simrick was saying about the 0x2 code. Whatever is happening it seems different than how it behaved before the AU.

 

Interesting. And today, for the first time, my Defender shows as running at 2:53pm, instead of the normal (around) noon time. I know the computer was on and not sleeping, as I was using it all that time. *Confused