Repairing disk permissions is a

troubleshooting Troubleshooting is a form of problem solving, often applied to repair failed products or processes on a machine or a system. It is a logical, systematic search for the source of a problem in order to solve it, and make the product or process ope ...

activity commonly associated with the

macOS macOS (; previously OS X and originally Mac OS X) is a Unix operating system developed and marketed by Apple Inc. since 2001. It is the primary operating system for Apple's Mac computers. Within the market of desktop and lapt ...

operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs. Time-sharing operating systems schedule tasks for efficient use of the system and may also in ...

Apple An apple is an edible fruit produced by an apple tree (''Malus domestica''). Apple fruit tree, trees are agriculture, cultivated worldwide and are the most widely grown species in the genus ''Malus''. The tree originated in Central Asia, wh ...

. The efficacy of repairing permissions to troubleshoot application errors has been debated.

Overview

The

BSD The Berkeley Software Distribution or Berkeley Standard Distribution (BSD) is a discontinued operating system based on Research Unix, developed and distributed by the Computer Systems Research Group (CSRG) at the University of California, Berk ...

layer in macOS is responsible for file-system security, including the management of the

Unix Unix (; trademarked as UNIX) is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, and ot ...

(

POSIX The Portable Operating System Interface (POSIX) is a family of standards specified by the IEEE Computer Society for maintaining compatibility between operating systems. POSIX defines both the system- and user-level application programming interf ...

) permissions model. Applications depend on the correct assignment and interpretation of permissions in order to function properly. Repairing permissions involves checking the permissions of a set of files and folders on a volume with macOS installed against a list of correct POSIX permissions and correcting any discrepancies. The list of correct permissions is compiled by consulting the various bill-of-materials (.bom) files. Typically, these files are stored within reduced-size Installer package (.pkg) files in the Receipts folder in the local Library directory () on the volume being checked. Whenever a user installs software that uses the macOS Installer package format, a bill-of-materials file is created which can be consulted for future permission repair. Files whose permissions have been incorrectly altered by an administrator, an administrator operating with root privileges, or a poorly designed installer package (installed with similar privileges) can cause a wide array of problems ranging from application errors to the inability to boot macOS. Repairing permissions can become necessary, but has become increasingly less so for versions after

Panther Panther may refer to: Large cats *Pantherinae, the cat subfamily that contains the genera ''Panthera'' and ''Neofelis'' **'' Panthera'', the cat genus that contains tigers, lions, jaguars and leopards. *** Jaguar (''Panthera onca''), found in So ...

(10.3). In

OS X El Capitan OS X El Capitan ( ) () is the twelfth major release of macOS (named OS X at the time of El Capitan's release), Apple Inc.'s desktop and server operating system for Macintosh. It focuses mainly on performance, stability, and security. Following ...

, Apple introduced a security feature called System Integrity Protection. With it enabled, root privileges are no longer able to change system files and folders, including their permissions. Permissions repairs are instead performed automatically upon system installs and updates. To that end,

Disk Utility A disk utility is a utility program that allows a user to perform various functions on a computer disk, such as disk partitioning and logical volume management, as well as multiple smaller tasks such as changing drive letters and other mount poi ...

as well as the corresponding

command-line utility A console application is a computer program designed to be used via a text-only computer interface, such as a text terminal, the command-line interface of some operating systems (Unix, DOS, etc.) or the text-based interface included with most gr ...

lost the ability to repair permissions.

Usage

In systems prior to OS X El Capitan, a permissions repair can be performed by selecting a startup volume and clicking the "Repair Disk Permissions" button in the "First Aid" section of Disk Utility. The operation can also be performed by using the command-line utility. In El Capitan, the user can instead use two command-line utilities: to repair particular packages or to repair a standard set of system packages. In both cases, the user has to disable System Integrity Protection to change permissions of system files and directories. In macOS Sierra, is not available. Permissions can also be repaired using

third-party Third party may refer to: Business * Third-party source, a supplier company not owned by the buyer or seller * Third-party beneficiary, a person who could sue on a contract, despite not being an active party * Third-party insurance, such as a Veh ...

utilities such as The Apotek's AppleJack or Prosoft Engineering's Drive Genius.

References

{{reflist Apple Inc. software MacOS