1. what version of Mcafee have you got 11.6 or 12.1?
2. If 12.1 did you update automatically from 11.6 or uninstall reinstall the software?
3. I would consider a clean reinstall following this method
reboot and run
and reinstall from your account
4. If that fails call support and see if they can see the issue or know of a fix.
BTW have you disabled the firewall does this help? Could point to the cause.