Why does Action Center tell me "Windows Defender needs to scan?"

ALN · 13 Jul 2016

It's my understanding that Defender scans according to Microsoft's maintenance schedule. But I get a notice in the Action Center that "Windows Defender needs to scan." My last scan occurred 4-5 days ago when I noticed the alert.

Is it possible that since my computer is powered down at bed time that the scheduled scan is skipped (and not started next morning when I power it up?

How often is Defender scheduled to scan?

Thanks for your help!
Al

Cliff S · 14 Jul 2016

If the computer is powered down at maintenance time, it will do it the next time you power up(and after a few minutes when the PC is idle).

Why does Action Center tell me "Windows Defender needs to scan?"-image-001.png

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Do you possibly have Windows Defender checked in Disk Cleanup?

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Uncheck as it clears Defenders logs, and Windows will think you have not run a scan yet.

Same thing goes if you have Ccleaner:

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ALN · 14 Jul 2016

Thanks Cliff S for the very detailed reply. My Task Scheduler settings are as shown in your illustrations, so looks like Defender is scheduled to run at power up. I do run Disk Cleanup on occasion, and if it detects Defender files, I would not have omitted them from the clean up options (At this time, Defender does not show up in clean up). I also run CCleaner regularly, and I did have Defender ticked for clean up. So looks like that was the issue. Thanks again for your work on this site!

Cliff S · 14 Jul 2016

You're most welcome:)

eLPuSHeR · 15 Jul 2016

I have never had any trouble cleaning WD data with the built-in disk cleanup util. CC on the other hand...