[German]Brief question for the Windows users among my blog readers: Did any of you experience problems with Microsoft Defender on Windows 10 or Windows 11 on August 18, 2026? I've received two reports from readers stating that Microsoft Defender crashes during a quick scan on all versions of Windows. And I found several posts in the internet, claiming Defender issues.
Several reports about defender crashes
German blog reader Ricardo has posted the information in the discussion forum on August 19, 2026, at 12:03 a.m. He wasted his workday on August 18, 2026, from around 3:00 p.m. until after midnight because Microsoft Defender could no longer complete quick scans after a security update.
The problem: The quick scan stops at about 80%, and the threat protection service shuts down. According to readers, this service can sometimes be restarted—but sometimes the threat protection service doesn't become active again until after a system restart.
I got also a 2nd report from a blog reader via email, claiming defender crashes during quick scan. Windows Defender is still working fine for me on my test system. But I found similar reports on Microsoft Q&A and on reddit.com. More details may be found within my German blog post [use the blogs build in translation to read the blog post in English].
