Skip to main content

Windows 10 update breaks Windows Defender antivirus: Here's the fix

(Image credit: Laptop Mag)

Checks watch. Oh, right, It had been more than a few hours since the last time Microsoft broke Windows 10, so it was past due. Sure enough, the latest Windows 10 update is causing Windows Defender to act up. 

Without a functioning built-in antivirus software, Windows 10 users are potentially being left open to attack. Once again, it's Windows Latest that did the digging and found reports from understandably ornery Windows 10 users who received "Threat service has stopped. Restart now" and "Unexpected error. Sorry, we ran into a problem. Please try again" errors. 

Some users are blaming Windows 10 version KB4549951 for the Windows Defender snafu but Windows Latest says Security Intelligence 1.313.1638.0 is the real criminal. Members on the Windows Community forums were frantically working out a solution but to no avail. 

The error messages are one thing but what's really concerning is that the flaw is preventing people from running Windows Defenders scans, potentially leaving them open to security attacks. Both full and quick virus scans are not functioning properly. 

“It happened this morning. Yesterday was fine. I tried everything, nothing worked. It seems to be a Windows glitch that needs to be fixed asap. It starts scanning and breaks in the middle of the scanning process around about 1/3 of the entire process,” one user wrote.

Windows Defender bug: What to do

Microsoft quickly released another update that patches the Windows Defender bug. To install it, type Windows Security in the search blank and select the Windows Security app. Here, click Virus and threat protection and look for updates. Once that finishes, Windows Security should work again.

This certainly isn't a good look for Microsoft, which continually proves incapable of releasing an update without breaking things along the way. At least, in this case, Microsoft acted quickly and pushed out a more stable update (fingers crossed) within 24 hours.