What's your operating system and is it totally up to date and is your internet connection always on.
Have you made sure that any previous security software has been totally removed, even using their removal tool if any?
(That's the usual reason for partial installation failure)..
Uninstall all McAfee currently installed via Control Panel > Programs and Features
Then run the MCPR cleanup tool and reboot.
Install the software from your online account if it exists or whatever means you have.
If all that fails I recommend Technical Support by phone, it's free of charge. Link below.
Toronto ▪ Canada
Volunteer Moderator - Consumer Products
I CAN'T HELP PRIVATELY - PLEASE POST IN THE FORUMS
Use Advanced Search To Find Answers
Please contact our Technical Support from the below link whom will assist you with Install. If already contacted, help me with the Service request number to investigate.