No, it is blocklisted by Mozilla due to that Site Advisor extension being the #2 cause of crashing the Firefox 5.0 betas. McAfee was notified of the problem long before that extension was added to the blocklist. Now it is up to them to fix it.
https://addons.mozilla.org/en-US/firefox/blocked/

I have read that McAfee is working on a re-written version that is projected to be available in the 3rd week of July.

Thank you. Very helpful and hope it gets fixed. Thanks again.

AWBz

I have just contacted McAfee support and they told me that when Mozilla releases Firefox 5.0 (not beta), the siteadvisor will work. In other words. they are saying it is a Firefox problem and not a McAfee problem.

Firefox 5.0 was released almost 5 weeks ago on June 21st. Heck, in another 10 days Firefox 6.0 is going to be released, I wonder what McAfee's excuse is going to be then.

I have no SiteAdvisor "site rating icons" using SiteAdvisor 3.4.1.195 (current as of 4/15/2012) and Firefox 11.0 McAfee tells me today that SiteAdvisor does not work with FF 11, but does work with FF 10 and earlier. Can anyone verify or deny the truth of this? My SiteAdivsor works OK with IE8. I'm on WIn XP and up to date.