Be it online or offline user get 24x7 support for activating mcafee antivirus from mcafee.com/activate. Though the activation process is simple however there are prerequisite to make your device ready before activating it in your device. you need to check whether your device all the files support mcafee, else even after installing and activating mcafee it will not work or you may get activation error. The most probale cause of activation error is support file in registry which generally corrupted when you are using your computer device from long time. There are issue due to your windows or mca computer firewalls as well which restrict some files to be installed while installer fetch it online during installation process. also if the threate is already install on your computer device it will restrict some file of mcafee.you need now to worry about it just contact support either over phone or chat to avail support for mcafee activate.