Without fanfare, on Thursday Microsoft released version 2 of its Microsoft Security Essentials (MSE) antivirus software. The software is free for individuals and small businesses with up to 10 PCs.

The new version of the software, which recently went through a four-month beta program, now has an overhauled heuristic antivirus scanning engine, integration with Windows Firewall, and network traffic inspection for Windows Vista and 7 -- but not XP -- reported Ars Technica.

On Thursday, Microsoft also announced that the not-free Forefront Endpoint Protection 2010 -- aimed at larger corporate users -- would be available from January 1, 2011. Forefront offers similar functionality to MSE, as well as centralized administration.

According to internal Microsoft research, 80% of PC users in the United States think their antivirus software is up to date. But in reality -- thanks to outdated signatures or lapsed trials -- only about 40% of Windows users are employing up-to-date antivirus software.

Why, then, wasn't there more fanfare for the latest version of a free antivirus program that's earned plaudits? The United Kingdom's PC Pro magazine said the stealth release might have to do with the software looking less like its previous, standalone antivirus scanner incarnation, and more like the security software offered by the likes of Symantec and McAfee. With MSE 2, according to PC Pro, "users are now asked whether they want to turn on the Windows Firewall during installation, dragging Security Essentials closer to becoming a full-fledged security suite."

Microsoft has recently come under fire from some antivirus firms for apparently muscling onto their turf. In November, after Microsoft began automatically installing MSE onto PCs that lacked antivirus software, Trend Micro slammed Microsoft on competitive grounds.

In a similar vein, Panda Software blogged that Microsoft was threatening PC users by creating an antivirus monoculture. According to Panda, "Microsoft should offer the complete portfolio of more advanced and secure alternatives of free antivirus products and time-limited versions of paid security suites, allowing users to choose any of them from the Optional Windows/Microsoft Update." Microsoft doesn't appear to have pursued this strategy.

Interestingly, Microsoft's release of MSE 2 comes on the heels of a new study from German AV vendor Avira, which found widespread dissatisfaction with antivirus. According to the survey of more than 9,000 Avira users, 25% of antivirus users admit to pulling the plug on their antivirus software -- at least temporarily -- because it appeared to be slowing their computer. Furthermore, nearly two-thirds of respondents have tried multiple security products on their PC in the past year.

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