A new version of Microsoft Security Essentials (2.0.657.0) was released today. You can download it from http://www.microsoft.com/security_essentials/?mkt=en-us (not sure whether other regions are updated yet, try it by yourself). Or you can wait until Windows Update offers it (not yet available)."192 GB ought to be enough for anybody." (from the miniseries "Next Generation's Jokes")