Microsoft Fixes Windows Defender Crashes After Security Update
Microsoft has fixed Windows Defender crashes linked to a recent security update. The problem affected some Windows 10 and Windows 11 devices. Affected users saw a “Threat service has stopped” message during security scans. Some quick and full scans also failed or forced the Defender service to restart. The issue caused 0xc0000005 access violation errors on affected systems. Reports appeared across social media and Microsoft’s support channels earlier this week. Microsoft confirmed the problem and released a fix through a new security intelligence update. The company recommends enabling automatic updates or installing the latest update manually.
The fix arrives with Microsoft Defender Antivirus signature update version 1.457.236.0 or later. Users should also check Windows Update for any pending updates.
How Users Can Fix the Problem
Users should first install the latest Windows updates on their devices. Next, they should confirm that Defender has received security intelligence version 1.457.236.0 or newer.
After updating, users can run another quick scan to check whether Defender works normally. The update should automatically apply the fix once the required signature version installs. This incident follows other recent Defender problems. In May, the security software mistakenly flagged DigiCert root certificates as malware.
That incident created false-positive alerts for many administrators. In some cases, Defender also removed affected certificates from Windows trust stores. Microsoft Defender also experienced a major portal outage in December 2025. That disruption affected some Defender XDR features and threat-hunting alerts.
The Latest Crash Issue Highlights
The importance of keeping security software updated. However, security updates can sometimes introduce unexpected problems.
Microsoft has now resolved the current Defender bug through its security intelligence update. Therefore, affected users should update their systems before running further scans. Keeping automatic updates enabled can also help users receive future fixes quickly.
