A Microsoft spokesperson told me that the beta is publicly available to users who are registered with Microsoft Connect, however, a limited number of beta downloads are available. The company had previously indicated that it would limit the number of beta testers.

It’s a product from Microsoft and can be installed in genuine Windows OS.

The software will support Windows XP with Service Pack 3, Windows Vista with Service Pack 1 or 2, and Windows 7 with Service Pack 1. Download Microsoft Security Essentials (MSE) Offline Installers (64-bit, 32-bit) - Last updated on Octoby VG Microsoft Security Essentials (MSE) is one of the best antivirus and antimalware product which is available absolutely free to download. You can download both versions in one shot or separately depending on whether you're running a 32-bit or 64-bit version of Windows. Microsoft is offering two editions of the Security Essentials beta-a 64-bit version called mseinstall-amd64fre-en-us.exe and a 32-bit version called mseinstall-x86fre-en-us.exe. And then clicking on that title finally takes you to the page where you can actually download the software. Clicking on the link to the download page (listed in Step 2 of the instructions) displays the title of the file-MSE Public Beta.

You'll then see a page describing the features in the new beta along with the system requirements and installation instructions.

Mseinstall 64 bit