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Microsoft Defender signature update fixes scan-crash bug on Windows 10 and Windows 11

Security Tool/Service
First reported
Last updated
Happening score
H score 11
1 unique sources, 1 articles

Summary

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Microsoft Defender now has a fix for a crash bug that broke scans on some Windows 10 and Windows 11 systems, restoring malware protection after a recent security update. The issue caused 0xc0000005 access violation errors and interrupted quick and full scans. Microsoft delivered the remedy through Microsoft Defender Antivirus signature update version 1.457.236.0 or later and advised customers to apply the latest update or keep automatic updates enabled.

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Timeline

  1. 19.08.2026 14:14 2 articles · 2h ago

    Microsoft Defender signature update fixes scan-crash bug on Windows 10 and Windows 11

    Initial Disclosure

    Users on Windows 10 and Windows 11 began seeing "Threat service has stopped. Restart it now" messages and scan failures after a recent security update. Some affected systems repeatedly crashed Defender during quick or full scans and needed service restarts to recover.

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