addon program what do you mean by that? Mcafee internet security is a full blown program that adds onto nothing. Did you buy it via subscription of in a box from a store?
If it is the legit program did you have another AV installed and if so did you remove it via its own removal tool?
Also remome mcafee via the method described here
reboot and run
and reinstall from your account
Then if still an issue call tech support
I recvied McAfee with a lenovo computer i had recently purchased. Recently the trial period was up and i clicked on a link given from the progam itself to renew my subscritiopn.
I also was under the impression that the Internet Security part was an addon since i thought at the end of the purchased i was asked for it for an additional slight cost.
also going throught the above posted steps.