Windows Defender, "Items Skipped During Scan"

As a side note, if you don't believe your core issue has been answered, you shouldn't mark anyone's post as such even if it's been helpful.  Otherwise, most will consider the issue resolved.

Instead, select the "No" option or simply leave it unselected.

Rob

The fact that most indicating they have this problem don't appear to have an exclusion, along with the nearly certain relationship to the monthly cumulative update, makes me think the cause is something else.

The description for this notification is found in the following document.

Hide notifications from the Windows Security app - Windows security | Microsoft Docs

Item skipped in scan, due to exclusion setting, or network scanning disabled by admin	The Windows Defender Antivirus scan skipped an item due to exclusion or network scanning settings.	ITEM_SKIPPED	Yes

Since the exclusion doesn't appear to be the issue, what about the other option of a network scanning setting?  In the search for that notification, this earlier thread appeared to have had similar issues due to a possible earlier infection that created an .ISO file mounted as partition G:\

Defender skips scanning an element because of exclusion or network settings - Virus, Trojan, Spyware, and Malware Removal Help

Now I'm not saying this might have been caused by similar past malware, but it does bring to question whether those affected might have additional drives or partitions defined, especially network drives such as a NAS, server or even an ISO file as did the person in that thread?

So rather than beating a dead horse and waiting for Microsoft to respond, which by its very nature won't occur until their developers are certain they've fully explored the potential reasons for the problem and likely delivered the solution as well, you may want to explore the other potential causes as well.

Rob

Rob: Thanks for your input, and without any disrespect intended. and with reference to your final sentence, the real problem for me is I have wasted countless hours of precious time jumping through such hoops only to find later that I was chasing a demon that didn't exist because of a bug in a Microsoft update.  One great example of this was the Windows Defender version 4.18.1908.7 update bug.  Please understand that I run other operating systems on other boxes and never have wasted time troubleshooting "phantom" problems like I have experienced with Microsoft after bad updates.  And for some Windows 10 updates I have even had  to disconnect all external USB drives to recover secondary internal hard drives in my Windows 10 box following an update and then reconnect them just to get my system back to normal. 

However, I am so heavily invested in coding Office software (including MS Visio and MS Project) for interoperability that relying only on those other OS's is not always pragmatic.  In my case, following your advice in your last sentence would only be setting myself up to exacerbate my problem of wasting time, as I have already done my due diligence and eliminated several potential possible causes without question.   If Microsoft was a bit more responsive to its consumers, it would be wonderful, but I fear there will be no trend toward that anywhere in the near future.

Actually ChipmunkLover, you and I agree, you simply took my final sentence as an instruction that you must perform those actions, when what I intended was to let those less knowledgeable about the almost inevitable delays in response know they shouldn't hold their breath.

As those with a background in development like yourself know, a company the size of Microsoft with the literally billions of customer devices and likely millions of slightly different device configurations is highly likely to experience a number of such issues every time a cumulative update is released.  Even with a structured testing program like the Windows 10 Insiders, there will be issues discovered after an update that either weren't seen during the testing phase or were rare and not severe enough that they'll be allowed into a release.

This situation appears to be one of those, where an apparently non-critical, but annoying notification is being displayed for a relatively small number of users for an as yet unconfirmed reason.

So I'm not telling anyone they have to do anything, only offering what I believe is a more likely path to determine the potential reason for the notification if they wish, rather then beating their heads against what to me seems an unlikely idea that a non-visible exclusion may be causing the anomaly.

Otherwise, your core advice is sound, just wait for Microsoft to fix it and relax.  No one has yet indicated this issue seems to disable Windows Defender's ability to operate or protect a system, only that some are wondering whether it might,  To me that seems unlikely and I'd simply ignore it, but how each person deals with this situation is up to them.

Rob

In its current state, I simply refuse to trust the PC to not have a vulnerability, even if one "doesnt seem likely." 

My PC has been off, aside from daily updates and MBAM scans, since this issue appeared. Its impossible to have faith in your PC with bugs like this, especially with people who dont know enough about PC's to feel anything but stress when this sort of thing happens.

I have another PC which has been issue-free, and I've been using that. This has all just been too much for me. If it weren't for game developers being so Windows-centric, I'd have given up on Windows 10.

Please, Microsoft, if you're reading this, stop stressing me out like this.