Repair Disk Permissions (& other disk and maintenance issues)

Article contributed by Beth Rosengard, Corentin Cras-Méneur, & Mickey Stevens

Word needs to be able to read and write to a wide variety of files in a range of directories.  If you have damaged folder permissions or disk files, it will be unable to do so properly.  Repairing Disk Permissions fixes a wide range of troubling behavior and should typically be your first troubleshooting procedure (after updating your software and rebooting your computer)

Repair Disk Permissions

MacOS X inherits many of its characteristics from UNIX.  For instance, most files are now bound by highly configurable read, write and execute permissions based on both the owner and the “group” a file belongs to. Some applications (especially installers) don’t deal with permissions as carefully as they should and can alter the proper permissions settings of various files and folders. User errors can also generate a lot of issues (especially when switching back and forth from MacOS 9 – which doesn’t “care” about permissions – to OS X, and when moving files around in OS 9).

Usually the System can fix these issues. The System stores a “Bill Of Material” (BOM) from each MacOS X savvy installer (usually a .pkg installer) which describes the proper permissions settings for all the files a program’s installer created. The System also comes with its own set of BOM files. When the permissions on your Mac are not properly set, you can ask the System to use the information in the BOMs to reset the proper permissions on all the key files and folders by repairing permissions as follows:

You should restart your computer after running a disk repair utility.  Processes which are run at the system level will not benefit from the repair procedure otherwise.

Tip:  Some sources advise repeating the above procedures repeatedly until no more issues are discovered by Disk Utility.  Apparently not all problems are fixed on the first run-through.

Note: On occasion, Disk Utility itself or the Repair Disk Permissions tool is affected by permissions issues.  There is a another option, using the Terminal, that works for all versions of OS X and which is even faster.

Open the Terminal (in /Applications/Utilities).  Type “sudo diskutil repairPermissions /” (without quotes and note the space before the slash).  When prompted, enter your administrator password and don’t be disconcerted that you don’t see anything as you’re typing.  When the procedure is complete, quit the Terminal.

General Disk Repair

If you are having trouble with more than just Word and repairing disk permissions did not help, there could be more serious structural disk problems. 

Begin by running Disk Utility (“First Aid” pane), which is installed with the System.  There are several ways to launch this utility.  The easiest is by starting up the computer in Safe Mode, which will automatically run the utility.  This feature is only available in OS 10.2 and later. Simply turn on the computer and, when the tone sounds, press and hold the Shift key.  The computer will run Disk Utility on the startup drive.  When startup is complete, restart your computer normally. If it doesn’t work, you can try rebooting on the System CD that shipped with your Mac and run Disk Utility from there. If you are not able to complete a Safe Boot because you do not have the required OS, use one of the alternative methods discussed on the Apple Knowledge Base [Lene Fredborg, 4-Feb-2019: Removed outdated link to] to run the utility.

If Disk Utility does not cure the problem, try one of the more advanced third-party disk repair utilities.  Currently, the most popular disk repair applications for the Mac are DiskWarrior from Alsoft, Drive Genius [Lene Fredborg, 13-Jan-2020: Removed outdated link] from Prosoft Engineering and TechTool Pro 4 from Micromat (requires OS 10.2 or later; if you are running an earlier version of OS X, consider Drive 10).  Since each of these utilities has its strengths and weaknesses, in extreme cases of disk damage, you may wish to run more than one.

Notes:  DiskWarrior is a very powerful repair utility but it has the nasty habit of disabling journaling on the disks it works on. You’ll need to use Disk Utility on MacOS 10.3 to re-enable journaling on the disk after the repairs. This does not apply to previous versions of the system.

Deleting System and User Cache Files

On some occasions, the system or user cache files can become corrupted. When this occurs, the system may have trouble launching some applications and/or the Finder may not be able to properly link files to the corresponding applications. Even though there are ways to delete these files manually, we recommend using a third party utility such as Cocktail [Lene Fredborg, 8-Sep-2018: Removed outdated link to] (shareware) or TinkerTool System (shareware). These applications (which provide many other useful maintenance tools) make the process much smoother. Once these applications have completed deleting the cache files, you MUST reboot the Mac. Most files will then appear without their customary icons but the icons will be restored when you launch their respective applications, re-populating the System and User cache.

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