Microsoft Security Essentials ranked second last in AV-Test's protection rating

Microsoft's free antivirus solution for all Windows users may be good in terms of usability - in particular, its impact on system performance - but when it comes to actual malware protection, it came almost dead last amongst its free and paid competitors in tests conducted during the first quarter of 2011 by German testing firm AV-Test. In fact, an almost identical observation can be made for AV-Test's previous tests conducted in the fourth quarter of 2010 on Windows Vista. Fortunately for Microsoft, despite these results the product did manage a pass and a certification from AV-Test.

The results were spotted by PCWorld, who are quick to point out that despite MSE's poor showing, it performed very well on samples of widespread malware and those on AV-Test's reference set that were discovered in the past two or three months. The problem is with 0-day samples and the resident scanner's ability to stop malware from running or after it ran. In particular, MSE caught only 50% of 0-day malware attacks in March, and only stopped 45% of malware from running. The industry averages are 84% and 62%, respectively. There were a total of 22 antivirus solutions tested.