Question 1: Read & Write - Allows a user to open the file and change it. To remove all existing permissions, set read and write access for the user while allowing read access for all other users, type: chmod u=rw,g=r,o=r file. ) This is what we are repairing when we use Disk Utility to “Repair Permissions. Change file permissions mac They’re designed so that certain programs (or other users if you share your Mac) can’t just dip into a system file they have no business with and modify it.