Over the weekend, security researcher Abdelhamid Naceri (also known as Nightmare Eclipse) released another Microsoft Defender zero-day exploit that blocks antivirus updates.

Serial Microsoft zero-day leaker NightmareEclipse has found another way to mess with Windows Defender, this time by stopping ...

A bad Microsoft Defender update is quarantining VLC's cache, causing severe startup delays. Here's how to fix it.

On some PCs, Windows 11 has been incorrectly warning that Microsoft Defender is turned off, even when it isn't, for almost ...

If you suspect malware, Windows Defender is a good place to start. But if it's not enough, there are plenty of other free ...

If your computer has suddenly slowed down compared to before, keeps freezing, or shows unfamiliar processes in the Task Manager, you should not ignore these signs. They could indicate the presence of ...

Microsoft fixes false Defender Antivirus disabled alerts with version 4.18.26080.4, resolving the issue across supported ...

A researcher who calls himself Nightmare Eclipse published a free tool on September 19, 2026, that can quietly stop Windows Defender from installing its own virus-definition and platform updates, ...

Discover September 2026 updates across Microsoft Defender, data compliance, endpoint management, and AI agent security.

Microsoft will retire the Calendar, People, and Files Microsoft 365 companion apps on December 16 and has asked admins to ...

Friday night. I was editing the instructions for my AI employees line by line again.I add notes to prevent the oversights ...

Das veröffentlichte PoC-Tool BigDiskBuster kann Defender-Aktualisierungen lokal ausbremsen; Microsoft hat bislang weder Advisory noch CVE genannt.