If you face different kinds of errors while conducting the activation process, there may be many reasons behind it. First of all, you should verify the selected language and Country. It must be the same that is presented on your retail card or matches with the information provided while purchasing online. Make sure that you are activating the McAfee Product Key for the first time and it is not used earlier by any other user. Also, the product key must not be expired, otherwise, you have to renew your product and then try for activation.