Users trying the Windows 7 beta who keep their computers safe with McAfee virus protection are in for a bit of disappointment -- and a loss of security. According to a Channel Web report, when you try to run McAfee Total Protection in the Windows 7 beta, an error message pops up. "The version of Windows installed on this machine is not supported. Please refer to the product documentation for a list of supported operating systems."

McAfee's antivirus tool isn't the only one affected by the Windows 7 beta. A thread on Norton's community forums mentions errors that occur when running Windows 7. The official response from Norton? "At this time, we do not support Windows 7. Once Windows 7 is released, we will provide solutions for the OS." In the past, prerelease copies or even early shipping versions of Windows updates were often flagged as "potential viruses" by antivirus programs (prompting lots of jokes about Windows being fingered as a virus).

One popular virus protection software that seems to be immediately compatible with Windows 7 beta is Spyware Doctor, which reports in its forums that the software is running smoothly.

Personally, I use Avast on my PC, although I haven't gotten around to checking out Windows 7 yet. It looks like Avast does have some issues, though for the most part it still runs in Windows 7.

The main problem seems to be that Windows 7 is still in beta, so no virus protection software has been optimized for the OS yet. As always when installing beta software, you do so at your own risk. Just know that this risk could impact your entire PC's security.