Long-time macOS (or OS X) users are familiar with terms such as “repair disk permissions,” which often comes up when troubleshooting a Mac. More often than not, this troubleshooting method comes first, as it’s quite easy to go through and can often lead to successful results.
However, what does “repair disk permissions” actually mean? And how do you repair disk permissions on the latest version of macOS? We’ll answer all of those questions, so keep reading.
First Things First – What Are File System Permissions in macOS (Mac OS X)?
Apple’s macOS is based on Unix, and just like Unix, it’s dependent on permissions. Every file and folder on your computer has a set of permissions. These indicate which users or applications can interact with certain files and in what way.
Files can have a range of permissions indicating which users can read, write, and execute the file and other more nuanced options. While this may seem unnecessary for an individual user’s laptop system, it’s a critical part of the operating system’s functionality.
What Causes File and Folder Permissions to Become Corrupt in macOS?
In older versions of macOS, apps could easily change individual permissions for files and folders in the home directory. As a result, permissions in the home directory could erroneously change and corrupt.
These incorrect permissions could cause all kinds of strange problems, making applications function incorrectly and sporting all sorts of strange bugs.
With incorrect permissions, applications and services could be denied access to essential files, causing them to crash or operate unusually. However, on a modern macOS system, home folder permissions are locked and much harder to access and change, meaning they can’t easily be messed with anymore.
What Does the “Repair Disk Permissions” Function Actually Do?
The “Repair Disk Permissions” function returns the home folder’s permissions to their expected state. Using this function, the home directory’s contents were checked against the “Bill of Materials” files found in “/var/db/receipts” and “/Library/Receipts.”
By analyzing those files, the operating system could determine what the home directory’s permissions should be and correct any discrepancies.
Is this Feature Available on All Versions of macOS?
Starting with OS X 10.11 El Capitan, you are no longer able to repair disk permissions explicitly. That’s because that feature was replaced by something called “System Integrity Protection.” That feature is designed primarily to prevent potentially malicious software from accessing important files on your Mac.
However, Apple didn’t really remove that option completely. Instead, you can still repair disk permissions on your Mac, even though this feature is now a part of something called “First Aid,” which bundles a group of actions that resolve all kinds of disk-related issues.
How to Repair Disk Permissions in macOS
Finally, the below instructions show how to repair disk permissions in macOS. Make sure to go through the following steps very carefully.
1. Open Disk Utility by typing “Disk Utility” into Spotlight (which you can launch by pressing Command + Space on your keyboard). You can also launch Disk Utility from “/Applications/Utilities/Disk Utility.”
2. Click on your boot volume using the pane on the left. If you didn’t rename the volume, it will be named “Macintosh HD.”
3. Click on the “First Aid” icon in Disk Utility’s toolbar (found in the top-right corner of the “Disk Utility” window) to start the repair process.
4. Read the confirmation dialog to confirm you’ve selected the correct drive, then click “Run” to start the disk repair process. Read the warning message as well, then click “Continue.”
5. During the repair process, your computer won’t respond to your input, which is normal and expected. The operating system needs to lock you out of the drive to make sure it can correctly analyze the drive’s contents. Even for large drives, it shouldn’t take more than a few minutes.
6. When the process finishes, you will see a report showing everything the First Aid process accomplished. If the process finds any serious errors, it will inform you of the problem.
Additional Tip – Should You Repair Disk Permissions on a Regular Basis?
Today, resorting to repairing disk permissions should only be done in one case – if you suspect that you have a file/folder permissions problem. This can happen to Mac users who install and delete software frequently.
That’s right – malicious software installers and installers that may not be properly optimized for macOS are what causes disk permission errors. With that said, be very careful about what kinds of software you download to your Mac, especially if they come with traditional installation wizards.
Don’t expect miracles from repairing your drive. Repairing disk permissions may fix some problems with your system but only if they’re related to issues with permissions. If you have other problems with your Mac, especially those related to performance, you may want to continue your search for a solution.
And finally, while we have your attention, we’re providing a few useful resources. Here’s how to customize the latest version of macOS – and make it truly yours. Also, here are the most interesting (and hidden) customization settings in macOS.