A little over a week ago, version 4.0 of Microsoft Security Essentials (MSE) was released. First seen in version 1.0 back in 2009, MSE has been among the top free antivirus programs ever since. I first mentioned it back in 2009, when it was in its testing stages, in one of my articles. I took version 2.0 for a test drive in 2011, where it performed surprisingly well. So I decided to take this version, 4.0 for a spin as well (there never was a version 3.0).

As I’ve usually done it, the test drive consisted of visiting known infected websites with my test computer, with the antivirus program installed and then observing and analyzing how the antivirus performs in terms of detecting malware, preventing the computer from being infected and cleaning it up as needed.

So I took my test computer and accessed 4 or 5 infected websites. One of them infected with a Trojan, one with a Fake Antivirus, one with a rootkit, and finally one with another Trojan. In each case the real-time protection feature of MSE correctly detected the presence of malware, stopped access to the infection, and cleaned up successfully any files downloaded by the website to my computer, without any user intervention needed. A detailed after-the-fact analysis of what went on when I accessed each infected website revealed that neither an invisible, behind-the-scenes infection nor computer settings alteration took place, confirming that MSE succeeded and passed the test.

I already liked MSE 2.0, and I’m liking MSE 4.0 even more. Out of all the free antivirus alternatives, it is the one I like the most.

If you have MSE in your computer(s), check to make sure you have this version, the latest. If you need help checking which version you do have or how to upgrade to the latest one, feel free to ask.