If you search "Smart Timer" here at the forums (see attached screenshot), you will find numerous threads about this.
Assuming your McAfee is properly configured and otherwise working correctly, then this probably explains your problem.
As you will see in the relevant threads, the mods have trying to get this feature removed/fixed/disabled, but there has been as yet no resolution from corporate.
(That said, I would be sure that your other security apps aren't running "active protection" modules, since they may be conflicting with McAfee. The one exception I have found is Malwarebytes Antimalware (MBAM) -- the registered/paid/PRO version's active protection module DOES play fine with McAfee on both my W7 Ultimate (64) and Vista SP2 Ultimate (32) systems. Indeed, it is designed to run alongside the major security suites.)
Hope this helps,