There are still many people around the world actively using IE6 and as many with it still installed but they use another browser as their default, Firefox, Chrome, Opera, etc., and IE6 lies in the background unpatched - hence a security risk.
Many processes rely on Internet Explorer without you knowing it, McAfee software included. So it is very important for security reasons as well as functionality, to use the latest available version in your machine, whether or not you use it.
For XP users IE8 is the highest version that can be installed (do not try to install IE9 as it isn't compatible), for Vista users - IE9, and for Windows 7, IE10 (now IE11 see). Windows 8 comes with IE10 anyway, 8.1 with IE11.
Please see IE6 Countdown for more information and an interesting chart.
Footnote: In Vista/Windows 7 64-bit (x64) systems if you use IE it should be the 32-bit (x86) version as most add-ons wont work with the 64-bit one....yet. With the IE11 update now available that has changed so I suggest upgrading to that a.s.a.p.
Also note that McAfee does not support beta versions of IE (and, in the case of SiteAdvisor, beta versions of other browsers), which have been shown to cause many problems, not least of which is a blank interface.
Toronto • Canada
Volunteer Moderator • McAfee Consumer Products