Microsoft Security Essentials (MSE) is a free antivirus software product for Microsoft Windows operating systems that provides protection against different types of malware such as computer virus, spyware, rootkits and trojan horses. Unlike the Microsoft Forefront family of enterprise-oriented security products, Microsoft Security Essentials is geared for consumer use.
Microsoft Security Essentials received positive reviews upon its release. In September 2011, it was the most popular antivirus software product in North America and the second most popular in the world.
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