Originating from OS X’s UNIX underpinnings, disk permissions dictate who is allowed to do what with each file or folder on your Mac’s hard drive. You as the administrator might have widespread access to read to and write from all files on your system, whereas a guest or a non-administrator account might be denied the ability to make changes to certain files.
While permissions exist primarily as a safeguard, they can sometimes cause issues when your system comes across a setting that is not what it thinks it should be. Luckily, repairing permissions is a simple process, and we demonstrate how to do it right here – with your permission, of course!
1: Open Disk Utility
The Disk Utility application used to repair disk permissions is found in your
Applications>Utilities folder. A handy keyboard shortcut to open this folder
quickly from within the Finder is Shift+Cmd+U.
4: Repair permissions
Click the Repair Disk Permissions button, then put the kettle on while the disk is scanned
for inconsistencies. It can take a while, depending on the size of your disk and how full it is.