Microsoft fixes a bug that slows down Firefox after five years

Have you noticed that your computer is slower when browsing with Firefox? This is due to a bug in Microsoft Defender, which has finally been addressed.

The problem is not from yesterday: the first report came in May 2018 error channel from Firefox. The browser increased Microsoft Defender’s CPU usage, which negatively affected browser performance. Oddly enough, this bug also became exclusive to Firefox, as Defender leaves Chromium Chrome and Edge browsers alone.

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Mozilla developers spent years trying to figure out what caused the problem, and only a month ago they came to the conclusion that it was due to Microsoft Defender’s built-in malware protection. The error causes more events that trigger Microsoft Defender. As a result, Defender calls VirtualProtect up to five times more often in Firefox than any other browser, increasing CPU usage by up to 75 percent.

dissolved after five years

Mozilla reported the problem to Microsoft and the two companies worked together to find a solution. It was released by Microsoft on April 4, almost five years after the first report. Normally, users do not need to do anything and Defender should update automatically. This update rolled out to Windows 7 and 8.1, although these versions of Windows are no longer supported.

You can verify this yourself by looking for the folder C:\ProgramData\Microsoft\Windows Defender\Definition Updates and then mpengine. dll Right-click. The correct version is 1.1.20200.4. App Defender should be in release 4.18.2302.x to sit down.

The fact that the problems at Mozilla have been going on for so long hasn’t been bad for Microsoft. Edge has been catching up with the latest Firefox releases since 2018. In 2018, Firefox was still the third largest browser and Edge was out of the question. Today Edge is number three with a market share of just under five percent; Firefox dropped below three percent (through statistics).