Microsoft patches Microsoft Defender false security alerts

Microsoft has released a patch for Microsoft Defender to resolve a bug that triggered false security alerts. The issue caused the operating system to display notifications claiming the antivirus had been deactivated, prompting users to attempt a manual restoration. In reality, the scanning engine remained fully operational in the background with all configurations active.

The error affected various platforms, including Windows 11 and Windows Server 2025, appearing at startup or randomly during sessions. The discrepancy between the actual service status and the interface messages caused significant confusion for IT departments, necessitating manual verifications. The corrective update, version 4.18.26080.4, aims to restore consistency between the protection services and the notification center.