Microsoft has released an emergency patch to resolve a persistent bug in Windows 11, Windows 10, and Windows Server. The issue, which first appeared in early August, caused the system to incorrectly notify users that Microsoft Defender was disabled.
Users frequently received notifications prompting them to reactivate the security service, even though the protection features remained active. The company confirmed that the bug affected all versions of the specified operating systems.
The fix was included in the Microsoft Defender Antivirus update, version 4.18.26080.4, released on September 17. The update is designed to install automatically on user devices.
To verify that the antivirus is functioning correctly, users are advised to open the Windows Security Center and check the timestamp of the most recent system scan.
