Is your system clock accurate, both time and timezone-wise?
What software are you using for your firewall?
What other security software do you have installed?
Is Windows 7 SP1 and totally up to date including IE11? (McAfee uses IE regardless of your default web browser).
The behaviour you are observing shouldn't be regarded as predictable, and although reported in these forums, isn't normal.
Thanks, Peter, for those ideas.
I did check, and have upgraded to IE11, but that has not solved the problem.
My firewall is Windows firewall, not McAfee.
System clock is accurate in all respects.
Any other thoughts?
Are you actually booting up or coming out of sleep or hibernation? I believe the software has been known to periodically fail in that scenario but Technical Support would be best to troubleshoot that. It's free of charge by phone or online chat and linked under Useful Links at the top of this page.
Before connecting it will ask you to run the Virtual Technician, which can sometimes fix things all by itself.
You can try it in advance here: http://mvt.mcafee.com/ if you want to.
Curiously enough, I ran Virtual Technician for about 12 hours and it never finished. I then canceled it.
It should only take minutes to run. You can either try the full uninstall routine: via Control Panel - Programs, then run MCPR cleanup, reboot and reinstall from the online account, or you can contact Technical Support - it's free and linked under Useful Links at the top of this page.