You would have had to uninstall or at least disable any antivirus software in order to install an operating system. The same applies to the installation of service packs.
There has been an upgrade release to bring the software in line with Windows 8 so if you now download from your online account it should be OK, however there is a proviso there.
If you obtain your software from a 3rd party, i.e. your ISP or your PC maker, they sometimes hang on to upgrades for an inordinate length of time and unfortunately there is nothing McAfee can do about that.
So if the software update hasn't reached you yet, you'll know because the software will install OK but will freeze when you try to navigate around SecurityCenter, you have a choice of simply waiting, or you could download the Beta software which is definitely compatible.
See HERE. You can always return to the retail product at a later time which shouldn't be long, hopefully.