Also it's on Windows 7
Make sure that operating system is totally up to date (7 SP1 + all subsequent updates), and even if you don't use it as your default browser, ensure thyat Internet Explorer is the latest version (11) and set to its defaults. The McAfee interface is essentially an IE webpage therefore sensitive to problems with IE.
In this instance I think the best way around this would be to uninstall McAfee via Control Panel > Programs, then run the MCPR cleanup tool and reboot, then reinstall from the online account.
Marking this thread as 'Assumed Answered' and locking it. As it s over 4 years old