Microsoft's free Security Essentials recently found itself in the crosshairs. Independent German security suite evaluators AV-Test.org publish bimonthly tests that rate the effectiveness of the biggest Windows security suites out there, and the recently published results showed that MSE failed to earn certification on the most recent test. MSE was the only suite to fail out of the 24 suites tested on Windows 7 during September and October. "Microsoft is offering a baseline protection with MSE. However, the majority of free and paid security offerings from third parties includes a better protection against current threats," wrote Andreas Marx, CEO of Av-Test.org. Most troubling are the low blocking rates against zero-day malware. MSE stopped only two-thirds of them, whereas many competitors did significantly better. Blocking zero-day threats is "the most important feature in today's protection mechanisms," since more than 90% of malware comes from web sites distributed by downloads or e-mail attachments Microsoft responded "Microsoft prioritizes protection based on impact and prevalence of malware affecting Microsoft customers from a global perspective. The Microsoft Malware Protection Center actively supports third-party testers to use similar methodology in their test results. We reaffirm that Microsoft is committed to providing a trustworthy computing experience and continues to invest heavily in continuously improving our security and protection technologies." The news is potentially more damaging for consumers because Microsoft Security Essentials is used by nearly 27% of the market as of September. To be fair, 16 out of the 23 security vendors scored worse this time than during the previous Windows 7-based test in May and June. However, on the most recent test, MSE couldn't even crack the 70% barrier on zero-day prevention.