The activation serial number for McAfee antivirus software appears in a pop-up window after the user accepts the license agreement on preloaded PC versions. If the user has purchased a physical copy of the McAfee software, the serial number is usually on a printed card inside the box.
As of 2015, most new PCs come preloaded with a trial version of McAfee antivirus software. The user must activate the software after purchasing the PC. Once the user signs into or creates a McAfee account and reads and agrees to the license agreement, the serial number should appear in a pop-up window.
In some cases, a serial number is not necessary and it does not appear. If the user purchases a separate copy of McAfee software, the serial number should be on a card inside the box.