24 Sep, 2026

New Windows Defender zero-day blocks Microsoft antivirus updates

Over the weekend, security researcher Abdelhamid Naceri (also known as Nightmare Eclipse) released another Microsoft Defender zero-day exploit that blocks antivirus updates. Naceri named it BigDiskBuster and said it is similar to another Defender zero-day known as UnDefend, which he released in April and that allowed standard users to block definition updates. The security researcher added […]

2 mins read

Microsoft fixes bug behind ‘Defender Antivirus is turned off’ alerts

Microsoft has resolved a known issue that causes incorrect alerts warning that Defender Antivirus was turned off after installing recent updates. In a Windows release health dashboard update on Thursday, Microsoft said the issue was fixed in the Microsoft Defender Antivirus update (version 4.18.26080.4) released on September 17. The company acknowledged the bug in late […]

2 mins read

Microsoft asks users to ignore ‘Antivirus is turned off’ errors

Microsoft asked customers this week to ignore incorrect alerts that Defender Antivirus has been turned off after installing the latest Defender updates. Although this issue has been affecting users in the Release Preview Channel of the Windows Insider program since June, it appears Microsoft didn’t notice it until now. The erroneous alerts appear on affected systems in the Windows […]

1 min read