Common computer problems such as software crashes, lockups and power outages can cause issues with your Mac that you might not notice. You can easily repair the disk permissions on a Mac to help it run smoother and fix some performance issues.
When to Use Repair Permissions
You should use Repair Permissions if you experience a problem with an application, such as an application not launching, starting up very slowly, or having one of its plug-ins refuse to work. Permission problems can also cause your Mac to take longer than usual to start up or shut down.
What Repair Permissions Actually Fixes
Disk Utility’s Repair Permissions only repairs files and applications that are installed using Apple’s installer package. Repair Permissions will verify and repair, if needed, all Apple applications and most third-party applications, but it won’t check or repair files or applications you copy from another source, or the files and folders in your home directories. In addition, Repair Permissions will only verify and repair files located on bootable volumes that contain OS X.
- Launch Disk Utility, located at /Applications/Utilities/.
- Select the ‘First Aid’ tab.
- In the left-hand pane, select a volume you wish to run Repair Permissions on. (Remember, the volume must contain a bootable copy of OS X.
- Click the ‘Repair Disk Permissions’ button.
Disk Repair will list any files that don’t match the expected permission structure. It will also attempt to change the permissions for those files back to the expected state. Not all permissions can be changed, so you should expect some files to always show up as having different permissions than expected.