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Microsoft Defender Antivirus false 'turned off' alerts after latest updates

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

Summary

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Microsoft Defender Antivirus is showing false 'turned off' alerts after the latest updates, creating confusion on supported Windows client and server systems even though protection remains active. The warnings appear in the Windows Security app and can prompt users to click to turn Defender back on. The issue has been present in the Release Preview Channel since June and now includes Windows 11 26H1 and Windows Server 2025. Microsoft says a fix will ship in a future Microsoft Defender Antivirus update.

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Timeline

  1. 31.08.2026 11:29 2 articles · 13d ago

    Microsoft warns that Defender Antivirus status alerts are false

    Initial Disclosure

    Microsoft asked customers to ignore false Windows Security app alerts stating that Microsoft Defender Antivirus is turned off after the latest Defender updates; the antivirus is still functioning correctly, the notifications can appear when Windows starts and intermittently afterward, and the issue has affected Windows Insider Release Preview Channel users since June and supported Windows client and server versions including Windows 11 26H1 and Windows Server 2025, with Microsoft planning a future Microsoft Defender Antivirus update to fix it.

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