Windows Defender, Edge Update: Slow PCs, Errors

John Lister's picture

Current news floating around the Internet suggests that Windows 10 has developed a couple of bugs likely linked to recent updates, namely: slowed performance and confusing security scan messages. The good news is both problems can be solved to some extent.

One problem is with update KB4559309, which replaces the original version of Microsoft's Edge browser with a new version based on the same code behind Google Chrome.

Details are still hazy, but some users have reported general slowdowns after the update regardless of whether they use Edge. This can affect apps, games and web pages.

The usual solution for a problem likely linked to a specific update is to uninstall the most recent update, either through the Control Panel, or in more serious cases, via the Advanced Startup boot menu. Unfortunately it doesn't appear this particular update can be removed this way.

System Restore an Option

Instead, the best option seems to be the Windows System Restore option which effectively acts like a time machine and puts the computer back to the way it was at a specific point. This is accessible by searching for "recovery" in the Control Panel.

The downside is that if you haven't recently manually requested a system restore point, the most recent automatically created point will usually be the last time you added a new app or driver.

Manually Downloading the Update May Sidestep Issue

As the update rolls out gradually, some users may not have had the KB4559309 update yet.

One way to avoid it is to manually download the Edge update from Microsoft's site at It appears that this will stop computers trying to automatically install the problematic Windows 10 update. (Source:

Windows Defender Borked

Meanwhile, other users have reported Windows Defender attempts to remove suspicious applications, but then flags them again on future scans even though they are no longer there. This creates a loop of persistent warnings. (Source:

The bug appears to be that Windows Defender appears to be mistakenly "spotting" applications in its own history files. In theory, this should be a simple fix for Microsoft in a future update.

One solution appears to be to go into the Virus & Threat Protections section of the Windows 10 Settings Menu, choose the Manage Settings option and add an exclusion folder. When prompted to select a folder, go through to C:\Program Data\Microsoft\Windows Defender\Scans\History and add this as the exclusion.

What's Your Opinion?

Have you experienced either of these problems? Should Microsoft leave Edge to update and replace itself rather than using Windows Update to send out the new version? Do you actively create system restore points or leave it to automated settings?

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c'est ma's picture

Windows caused the d*mn problem, why isn't it up to them to fix it? I am SO SO SO SO SO sick of all the lost time, fear & angst these G*ddam "updates" wreak on the hapless user.

The last straw for me was the announcement, at the height of the original Covid-19 disruption, when people were working from home (if they were lucky), on leave, etc., and MS graciously announced it would limit its latest update due to the fact that so many customers no longer had access to their company's tech departments. Hey, MS, what about all us home users with no tech support whatsoever?!