[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"$fOoNmdJR15qUBBtBVycUyIZHXdv-Auo1vm2vqNDbITQw":3},{"article":4,"iocs":46},{"id":5,"title":6,"slug":7,"summary":8,"ai_summary":9,"brief":10,"full_text":11,"url":12,"image_url":13,"published_at":14,"ingested_at":15,"relevance_score":16,"entities":17,"category_id":28,"category":29,"article_tags":33},"827c2b83-67b4-4c1d-a507-9d1effa700b5","Microsoft fixes known issue causing Windows Defender crashes","microsoft-fixes-known-issue-causing-windows-defender-crashes-906994","Microsoft has resolved a bug that caused Windows Defender to crash after a recent security update, resulting in 0xc0000005 access violation errors on some affected systems. [...]","Microsoft has resolved a bug that caused Windows Defender to crash on Windows 10 and Windows 11 systems, leading to 0xc0000005 access violation errors. The issue, which began after a recent security update, prompted some users to restart the Defender service or even reinstall their operating system. Microsoft confirmed the bug and stated it has been addressed in a new signature update, recommending users apply the latest updates.","Microsoft fixes Windows Defender crash bug causing 0xc0000005 errors.","Microsoft fixes known issue causing Windows Defender crashes By Sergiu Gatlan August 19, 2026 07:14 AM 1 Microsoft has resolved a bug that caused Windows Defender to crash after a recent security update, resulting in 0xc0000005 access violation errors on some affected systems. Microsoft Defender is a security software designed to provide real-time protection against malware, viruses, ransomware, and spyware on Windows, macOS, Linux, Android, and iOS devices. According to reports on social media and Microsoft's support site, users began seeing \"Threat service has stopped. Restart it now\" error messages on Windows 10 and Windows 11 devices starting Tuesday afternoon, prompting some affected customers to reinstall the operating system. \"Beginning this morning, quick or full scans are failing, and will occasionally fail to the point where the Defender service needs to be restarted,\" one Windows system admin said. \"We came across this while responding to a separate infection - I chalked it up to Defender being borked due to the infection but then I was able to recreate the issue on other devices simply by initiating a Quick Scan.\" Threat service error (Anonymous) Microsoft has since confirmed this issue and told BleepingComputer that the bug has been addressed in a new signature update. \"We have addressed this with a fix and recommend customers apply the latest update or enable automatic updates,\" a Microsoft spokesperson told BleepingComputer. The company added that the fix will be applied automatically after installing Microsoft Defender Antivirus signature update version 1.457.236.0 or later. Affected users are advised to update their systems via Windows Update, then check whether they have the latest security intelligence update installed. In May, system administrators also reported that Microsoft Defender flagged DigiCert root certificate entries as Trojan:Win32\u002FCerdigent.A!dha malware, resulting in widespread false-positive alerts and, in some cases, removing certificates from the Windows trust store. Months earlier, in December 2025, a widespread Microsoft Defender portal outage blocked access to some Defender XDR portal capabilities and disrupted threat hunting alerts. Once attackers have valid credentials, only 37% of their actions are blocked Overall prevention scores can hide what happens after initial access. Once attackers are using valid credentials, prevention drops sharply.The Blue Report 2026 measures defenses technique by technique across 338 million simulations run in customer production environments. Get the report Related Articles: Microsoft working on Defender patch for ShieldBreak zero-dayWindows KB5121767 OOB update fixes shutdowns on some Dell PCsMicrosoft shares manual fix for WSUS sync delays and timeoutsMicrosoft confirms Windows Server Update Services sync delaysMicrosoft: Some Dell PCs shut down after recent Windows updates","https:\u002F\u002Fwww.bleepingcomputer.com\u002Fnews\u002Fmicrosoft\u002Fmicrosoft-fixes-known-issue-causing-windows-defender-crashes\u002F","https:\u002F\u002Fwww.bleepstatic.com\u002Fcontent\u002Fhl-images\u002F2021\u002F05\u002F26\u002FMicrosoft-Defender.jpg","2026-08-19T11:14:28+00:00","2026-08-19T12:00:09.220575+00:00",7,[18,21,24,26],{"name":19,"type":20},"Windows Defender","product",{"name":22,"type":23},"Microsoft","vendor",{"name":25,"type":20},"Windows 10",{"name":27,"type":20},"Windows 11","80544778-fabb-4dcd-aa35-17492e5dcf4f",{"id":28,"icon":30,"name":31,"slug":32},null,"Vulnerabilities","vulnerabilities",[34,39,41],{"category":35},{"id":36,"icon":30,"name":37,"slug":38},"02371804-cf6d-4449-98de-f1a2d4d9b266","Tools","tools",{"category":40},{"id":28,"icon":30,"name":31,"slug":32},{"category":42},{"id":43,"icon":30,"name":44,"slug":45},"89f78b1c-3503-45a1-9fc7-e23d2ce1c6d5","Malware","malware",[47],{"type":45,"value":48,"context":49},"Trojan:Win32\u002FCerdigent.A!dha","False positive detection by Microsoft Defender in May 2026."]