Repair disk permissions
Mac OS X uses permissions to determine which users and groups can access or change saved files. This allows Mac OS X, as a multi-user operating system, to maintain clear separation between files owned by one user or another. This separation provides security. It also helps system reliability and stability, because even administrator-level users have to make a choice to modify or delete system files.
From time to time, the permissions on your disk drive may become incorrect. This happens most often after a software installation -- either from Apple software or a third-party package. The folders and files whose permissions are incorrect are generally part of the operating system, and do not directly affect the document files you have saved. Because the incorrect permissions can affect both the security and reliability of your computer, we recommend you repair the disk permissions after every new software installation.
The Disk Utility application provides you with a way to repair the disk permissions. This can take a few minutes or more, and you can perform other tasks while the repair process runs.
If you prefer, you can also run the repair process from the command line.
Disk Utility
You will need the username and password for an administrator-level account on the computer. These instructions focus on the Mac OS X 10.3 "Panther" version of Disk Utility, but are similar to what is needed in older versions of Mac OS X.
- Launch Disk Utility.
- Select the disk whose permissions need repair from the list of disks in the Disk Utility window.
- Click on the "First Aid" tab in the right portion of the Disk Utility window.
- Click on the "Repair Disk Permissions" button.
Command line
These instructions will work in Mac OS X 10.2 "Jaguar" and later.
- Log in to Mac OS X as an administrator-level user.
- Open the Terminal application. It is found under "Utilities" in the "Applications" folder.
- Enter the following commands, printed in bold, at the command prompt.
% sudo diskutil repairPermissions /Note: You do not need to enter the "%," which represents the command prompt. - Press Return to complete the command.
- Enter your administrator password when prompted, and press Return.
On Panther systems with the Classic environment installed, you can also repair the permissions for the Mac OS 9 system used by Classic:
- Log in to Mac OS X as an administrator-level user.
- Open the Terminal application. It is found under "Utilities" in the "Applications" folder.
- Enter the following commands, printed in bold, at the command prompt.
% sudo diskutil repairOS9Permissions / - Press Return to complete the command.
- Enter your administrator password when prompted, and press Return.
