The issue reportedly first appeared in early August this year.
By Sam Ovie
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Published on September 20, 2026
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1 min read
Microsoft haz released an emergency patch this week to fix the “Microsoft Defender is disabled” error message that had persisted for nearly two months on Windows 11 and Windows 10.
The issue reportedly first appeared in early August this year. Some users experienced frequent push notifications in Windows Security Center stating that Microsoft Defender had been disabled and requesting that it be reactivated. However, when users actually opened Security Center, they found that the protection feature had been working normally all along.
Microsoft stated that the false positive issue affected all versions of Windows 11, Windows 10, and Windows Server. The issue was resolved in the Microsoft Defender Antivirus update released on September 17th (version 4.18.26080.4).
In theory, this update should install automatically. If you’re unsure whether Defender is functioning correctly, you can open Windows Security Center and check if the last scan was recent.
