Sorry for the inconvenience caused in activating McAfee products. Please run the mcAfee removal tool from here and restart the computer.
Try activating the products using the same product key and it should register through.
Please do let me know if any issues on the same.
McAfee Community Moderator
Discovered a quick solution. Rather than choose to use my old account settings to renew my subscription, I chose the option of opening a new account; I then answered that I already had an account, at which point I was prompted to give my username and password (up to this point I was not given that option). After submitting that, my subscription was activated immediately, but thanks for the response.
Glad that you found a resolution and thanks for sharing the same. Please do open a new thread if any issues.
McAfee Online Community Moderator