About the root user in Activity Monitor
OS X is a multiuser environment in which besides standard user and administrative accounts there are a number of hidden or background accounts that are reserved for system-level tasks. One of these is the commonly referenced "root" user, which is the main and fully unrestricted administrator account on the system.
Because the root user has unrestricted access to all aspects of the system, running it interactively can pose a security risk as well as result in inadvertent system alterations. Therefore enabling it is highly discouraged, and the only time we recommend temporarily setting its stats to "enabled,&… Read more