Also, if Mac has several user accounts, permission system will keep every user’s data private from other users. For instance, any applications are unable to modify the system files without permissions. Permission system is the way Mac system utilizes for data security. Now, this article will expose 4 rapid ways to repair disk permissions. So, it is serious that the disk permission is incorrect. Disk permissions on Mac system are actually file or folder settings that impact data read and write, program running and so on.