A recent update to Windows Defender and Microsoft Security Essentials is causing widespread problems for Windows users trying to scan systems for malicious files.  The glitch in Microsoft’s anti-malware is being reported by Windows 7, Windows 8.1, and Windows 10 users.  As per German tech blog Borncity, the file scanning issues emerged after Microsoft released an update to the Microsoft Malware Protection Engine (MsMpEng.exe) on September 16 that brought it up to version 4.18.1908.7.  The engine ships with several Microsoft anti-malware products for consumer and enterprise customers, including Windows Defender, Security Essentials and Forefront. And unlike normal Windows security updates, which give users some choice over when they’re installed, typically Windows Defender users don’t choose when the engine is updated because Microsoft deploys them automatically through an update manager.  The issue is affecting the ‘quick scan’ and ‘full scan’ options, with quick scans ending in seconds and only scanning between five and 64 files. Normally, thousands of files should be scanned in a process that takes around 30 minutes to complete.  But the bug means that Microsoft’s anti-malware isn’t doing the job it was intended for and as users point out, the software still displays a green tick mark and states the scan is ‘complete’, even though it’s clearly not.

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