Why and When You Need to Repair Disk Permissions

The short explanation is that Mac OS X incorporates a subsystem based on a UNIX-style operating system that uses permissions in the file system. Every file or folder on your Mac has permissions set to determine who can read, write to, or execute it: you (the owner), staff (a group of people) or everyone. Going further, this means that if you want to open a folder, you need to have the execute permission for that folder, so it makes sense that shared folders will have their permissions set to allow execute access to anyone.

• The changes made in System Preferences aren’t saved.
• The changes made to the Dock aren’t saved.
• You repeatedly get a message saying that macOS needs to fix your Library to run applications.
• Your Mac runs slowly, and more.

How to view permissions settings for a folder or file

1. Select the targeted file and hit the Command + I keys or select File > Get Info in Finder.
2. If the Sharing & Permissions section at the bottom of the window isn’t open, click the triangle to open it.
3. Adjust the permissions settings as needed and type in the administrator username and password if required.

With the introduction of System Integrity Protection in OS X El Capitan, however, Apple removed the repair permissions feature from Disk Utility, claiming that the system files are now protected from intentional and inadvertent change and therefore eliminating the need for this tool.

With macOS Sierra, however, Apple re-enabled it, but with a twist. Now, to adjust the permissions and apply the change throughout the home folder, you need to:

1. Select the home holder and click File > Get Info.
2. Click on the arrow at the Sharing & Permissions section to open it.
3. Type the administrator name and password after clicking on the lock icon at the bottom.
4. Click on the Action menu in the bottom corner, choose “Apply to enclosed items”, and confirm.
5. After the progress bar completes, continue the procedure by opening the Terminal appand pasting the following command followed by Return.diskutil resetUserPermissions / `id -u`
6. Quit Terminal once the process is complete.

For Mac users running El Capitan or earlier, OnyX or CleanMyMac provide the option to repair disk permissions as part of their maintenance features, so make sure you make the most of these commands – especially now that you know what it will be fixing.