What just happened? There once was a time when Microsoft’s Windows Defender was regarded as one of the worst options when it came to protecting your PC. But the free antivirus software has matured in recent years, and has just been ranked the joint top product in AV-Test’s latest report.

In the German independent research institute’s May/June 2019 ‘best antivirus software for Windows Home Users’ report, Windows Defender is one of four products to receive perfect 6 out of 6 scores in the protection, performance, and usability categories.

Windows Defender shared the top honors with F-Secure SAFE, Kaspersky Internet Security, and Norton Security, but Microsoft’s software has a significant advantage over those three: it comes free with Windows 10, while the others are paid-for options.

AV's test results show that Windows Defender managed to block 100 percent of its 307-sample zero-day malware corpus and 100 percent of its 2,428-sample general test corpus. The software was also shown to have little performance impact.

A couple of other free antivirus products just missed out on a perfect score. AVG and Avast recorded a total of 17.5 out of 18, both dropping half a point in the protection category. The lowest scorer, meanwhile, was Webroot SecureAnywhere 9.0, which had a total of 11.5.

Windows Defender has come a long way since it released as Microsoft Security Essentials a decade ago, after which it spent years regularly coming bottom in AV-Test’s results. Microsoft’s Corporate Vice President, Brad Anderson, promoted the good news on Twitter, adding that Defender is also the most commonly used Antivirus in the enterprise—it just missed out on another perfect score for business users.

Check this out. WIndows Defender classified as "BEST antivirus" by independent lab @avtestorg. As I blogged about last year https://t.co/PIUgTeq3dm Defender is now the most commonly used antivirus in the Enterprise and SMB customers. https://t.co/V4B9Yhe6Fv — Brad Anderson (@Anderson) August 7, 2019

You can download the latest Windows Defender definition updates here.

Do you rely on Windows Defender to protect your PC, or do you prefer a third-party solution? Let us know in the comments below.