If, after running MVT again, it's still acting up I would do the following:
Uninstall everything McAfee in Cintrol Panel > Programs
Run the MCPR cleanup tool and reboot.
Reinstall from the online account.
Also ensure Windows is totally up to date including ALL browsers and their add-ons. McAfee relies on Internet Explorer for functionality so make sure it is up to date too even if you don't use it.