Microsoft asks users to ignore 'Antivirus is turned off' errors

Following the installation of the latest Microsoft Defender Antivirus updates, affected Windows systems display erroneous notifications indicating that Defender Antivirus is turned off. This issue impacts all supported Windows client and server versions, including Windows 11 26H1 and Windows Server 2025. Despite the alerts, Defender Antivirus remains active and fully functional. The notifications appear on system startup and intermittently thereafter, persisting even if notification settings are disabled. Microsoft has confirmed the issue on its release health dashboard and is developing a fix to be delivered in a future update.

There is no actual security impact or vulnerability associated with this issue. The alerts are false positives and do not indicate that Defender Antivirus is disabled or non-functional. Users receiving these notifications remain protected by Defender Antivirus. The issue may cause confusion or concern but does not reduce endpoint security or increase risk.

Microsoft advises users to ignore the incorrect 'Antivirus is turned off' alerts as Defender Antivirus continues to operate normally. No immediate action is required. Microsoft is actively working on a fix, which will be included in a future Microsoft Defender Antivirus update. Users should apply the update once it becomes available to resolve the notification issue.