Windows Defender Crash Issue Resolved by Microsoft

Microsoft has resolved an issue causing Windows Defender crashes after a recent security update. The bug resulted in 'Threat service has stopped. Restart it now' error messages on some affected systems, prompting users to reinstall their operating system.

The issue began Tuesday afternoon and was reported by Windows system admins who noticed 'quick or full scans are failing, and will occasionally fail to the point where the Defender service needs to be restarted.'

Microsoft confirmed the bug and told BleepingComputer that it has been addressed in a new signature update. The company recommends customers apply the latest update or enable automatic updates.

Affected users can update their systems via Windows Update, then check if they have the latest security intelligence update installed. This fix will be applied automatically after installing Microsoft Defender Antivirus signature update version 1.457.236.0 or later.