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

Microsoft has fixed the bug that made Windows Security wrongly claim Microsoft Defender Antivirus was turned off. According to Windows Latest, the fix comes in Defender platform update 4.18.26080.4, ...

A researcher who calls himself Nightmare Eclipse published a free tool on September 19, 2026, that can quietly stop Windows ...

Microsoft has a new Defender anti-virus update for Windows 11 and 10 images. The new update patches several flaws.

After installing the latest Defender Antivirus update for Windows 11, users have started reporting that their operating ...

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

Microsoft has resolved a known issue that causes incorrect alerts warning that Defender Antivirus was turned off after installing recent updates.

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 ...

BigDiskBuster can block Microsoft Defender updates by filling disk space, leaving detection content stale; no patch or advisory exists.

A patch Microsoft released on Wednesday to fix a zero-day vulnerability in its Defender security engine may cause Windows machines to write files large enough to completely consume available disk ...