A feature of Mac OS X Version 11 (El Capitan) that prevents applications from gaining root access to the operating system. Included to make the OS more secure, numerous low-level apps from third-party developers are rendered unusable. OS X's Unix foundation normally enables users to have administrative (root level) access to the /bin, /sbin and /usr directories; however, starting with El Capitan, only the Apple installer can modify files in those locations. See
El Capitan.