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For more than five years, the troublesome security protection provided by Microsoft Defender was negatively affecting Firefox users during their web browsing sessions. The Antimalware Service Executable component of Defender (MsMpEng.exe) was acting strange, showing a high CPU usage when Firefox was running at the same time.
Users were complaining that Defender was stressing the CPU while the Mozilla browser became laggy and unresponsive. The issue was first reported 5 years ago, and it was seemingly a Firefox exclusive as it was sparing Edge and other third-party browsers like Chrome.
In March 2023, Mozilla developers were able to finally discover the source of the issue: while Firefox was running, MsMpEng.exe was executing a very high number of calls to the OS kernel's VirtualProtect function while tracing Windows events (ETW). VirtualProtect is a function to change the "protection on a region of committed pages in the virtual address space of the calling process," Microsoft explains, and Defender was doing a lot of "useless computations" upon each event while Firefox was generating a lot of ETW events.
Microsoft is also bringing the update to the now obsolete Windows 7 and Windows 8.1 systems, as Firefox will keep supporting the two operating systems "at least" until 2024. Furthermore, Mozilla engineers said that the "latest discoveries" made while analyzing the weird Defender bug would help Firefox "go even further down in CPU usage," with all the other antivirus software and not just Defender this time.
www.techspot.com
Users were complaining that Defender was stressing the CPU while the Mozilla browser became laggy and unresponsive. The issue was first reported 5 years ago, and it was seemingly a Firefox exclusive as it was sparing Edge and other third-party browsers like Chrome.
In March 2023, Mozilla developers were able to finally discover the source of the issue: while Firefox was running, MsMpEng.exe was executing a very high number of calls to the OS kernel's VirtualProtect function while tracing Windows events (ETW). VirtualProtect is a function to change the "protection on a region of committed pages in the virtual address space of the calling process," Microsoft explains, and Defender was doing a lot of "useless computations" upon each event while Firefox was generating a lot of ETW events.
Microsoft is also bringing the update to the now obsolete Windows 7 and Windows 8.1 systems, as Firefox will keep supporting the two operating systems "at least" until 2024. Furthermore, Mozilla engineers said that the "latest discoveries" made while analyzing the weird Defender bug would help Firefox "go even further down in CPU usage," with all the other antivirus software and not just Defender this time.
Microsoft fixes 5-year-old Windows Defender bug that was killing Firefox performance
Update (April 11): The Mozilla developer who worked on fixing this performance issue and reported it to Microsoft added the following on a Reddit thread, clarifying the...
www.techspot.com
