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Microsoft Patches Severe Windows Defender Bug

(Image credit: Michael Traitov / Shutterstock)

Microsoft patched a serious flaw in the Windows Defender security utility today. The issue resulted in certain malware scans failing after just a few minutes, per ZDNet, which found reports of this issue across social platforms like Reddit as well as tech support websites. Those failed scans could have left Windows users vulnerable to attack even though the operating system has a built-in antivirus solution that's supposed to keep them safe.

The issue followed an all-too-familiar pattern: there was a System File Checker bug in Windows that Microsoft attempted to fix with the release of Windows Defender version 4.18.1908.7 earlier this week. Instead of fixing the problem, however, the update reportedly messed up the process that allows Windows to scan files. An update released to fix one problem accidentally resulted in critical parts of Windows Defender malfunctioning.

This has become a trend with Microsoft. An update meant to improve wireless connectivity on Surface devices actually prevented them from connecting to some networks. A fix to a "SearchUI.exe" bug that resulted in high CPU usage broke Windows Desktop Search, and the update meant to fix search failed spectacularly, with users reporting that the update led to further issues with core parts of the Windows 10 experience such as Action Center.

At this point we're hoping this problem is limited to the Windows team, because if it extends to any of Microsoft's on-campus medical staff, employees might want to keep any health problems to themselves. Sore elbow? Maybe a broken arm will help. Runny nose? Well, noses are overrated, right? At least then Windows systems wouldn't be the only things exposed to infection because someone tried to keep up with important updates.

The good news is that Microsoft said it fixed this issue with the Security Intelligence Update for Windows Defender Antivirus – KB2267602 (Version 1.301.1684.0) release from this morning. But to be honest, by now we're just waiting for someone else to find out that something worse has happened as a result of this update. Things like this can only happen so many times before Windows users start to seriously doubt any software updates.