"I have McAfee Internet Security Suite on my system, and when IE 7 is loaded, neither work," one tester wrote in Microsoft's news groups. "Surely...getting the system to work with an industry leader is a small price to pay." ... Microsoft acknowledged the compatibility issues with the McAfee software in a response on the IE team blog. "The McAfee issue is known, and we'll work on this for a future build," a Microsoft representative wrote on the blog.
Despite the stigma against IE6 currently, IE7 is a very different beast and a second look is probably worth it. Anyone want to try it out should, but remember to never put beta software on production machines.