Windows Defender, "Items Skipped During Scan"

Hi SP. I'm Greg, an installation specialist, 10 year Windows MVP, and Volunteer Moderator here to help you.

Several people have reported the message lately which does not yet have an explanation. If you want to report this to Microsoft use the Feedback Hub app in Start Menu where developers are tasked to process consumer feedback. They will not even see it here. This is a tech forums staffed mostly by volunteers trying to help others with your problems.

If you want to post back a Share link from your Feedback here others who see this thread can vote it up and add to it. If you are an Insider I can also vote it up with my MVP badge and track the issue for you.

Make sure there are no exclusions following this guide:

https://www.tenforums.com/tutorials/5924-add-re...

Then Download, install and run a full scan with the most powerful on-demand free scanner Malwarebytes. This is a much better scan than what Defender can give, although Defender offers adequate real time protection:

https://www.malwarebytes.com/mwb-download/.

In the Malwarebytes Settings > Security tab set it to include scanning for Rootkits.

If necessary run it in Safe Mode with Networking, or Safe Mode accessed by one of these methods: https://www.digitalcitizen.life/4-ways-boot-saf...

Clean up anything found, restart PC and then run again until it comes up clean.

Then download, install and run a full scan with AdwCleaner:

http://www.bleepingcomputer.com/download/adwcle... Remove whatever it finds.

Check for any remainders in Settings > Apps > Apps & Features, and also in each of your browser's Extensions, Home Page settings, Search service or Add-On's as shown here: https://www.computerhope.com/issues/ch001411.htm

Then check for damaged System files by running System File Checker from Step 10 in this checklist:

http://answers.microsoft.com/en-us/windows/wiki....

If completing all of Step 10 in above Checklist doesn't fix it then run a Repair Install which reinstalls WIndows while keeping your files, programs and most settings in place, by installing the Media Creation Tool from this link http://windows.microsoft.com/en-us/windows-10/m..., open the tool and choose Upgrade This PC Now. This will solve most problems and also bring it up to the latest version which you need anyway and by the most stable method.

If you want to keep Malwarebytes as an on-demand scanner then you can turn off its Real Time trial version in it's Settings > Account Details tab.

I hope this helps. Feel free to ask back any questions and let us know how it goes. I will keep working with you until it's resolved.

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Standard Disclaimer: There are links to non-Microsoft websites. The pages appear to be providing accurate, safe information. Watch out for ads on the sites that may advertise products frequently classified as a PUP (Potentially Unwanted Products). Thoroughly research any product advertised on the sites before you decide to download and install it.

After discussing this behavior within my blog Windows 10: Defender skips elements during scan, the reason for the message became clear. Defender avoids to scan network files (I postulate, that Microsoft has changed that recently). 

You can ignore the warning - or you may use the workaround (which isn't recommended due to performance issues) discussed within my blog post Windows 10: Fix for skipped Defender scans. I've now proof, that the behavior has been changed in March 2020 within Defender's internal default settings (before March 2020 Defender scans network shares - now this is deactivated by default). 

HTH

Addendum: Microsoft has released an update to fix that behavior, see Update KB4052623: Microsoft fixes Defender ScanSkip Bug.

You know, it would be nice if Microsoft would either confirm or deny whether there is a bug, because surely, in their infinite wisdom, they would know by now.  Their handling of these kinds of things just seems to underscore the problems associated with a successful corporation getting too big with too much power and emphasizes the importance of strong federal antitrust legislation.

UPDATE: It appears this is a problem for multiple people, not just me. (Link goes to a Reddit post) That being said, it doesn't appear to be EVERYONE's problem, I checked another PC in my house and it doesn't have this issue.