Probably your best bet would be to uninstall the app and then restart. Then reinstall from your online account.
It may be easier for you to ask for help - it's free of charge and linked under Useful Links at the top of this page, then technical Support > Mobile Support.
Was there any new apps installed on your phone any other weirdness noticed. It is best to check installed apps before McAfee started scanning continuously. You may also initiate a full scan and wait for it to complete. Post back if McAfee scans repeatedly in 10 secs interval after successful full scan done.