In Mac OS X v10.5 or earlier, when you verify or repair disk permissions, Disk Utility reviews each of the.bom files in /Library/Receipts/ and compares its list to the actual permissions on each. You can repair your Mac’s permissions from the Disk Utility application. To open it, press Command + Space to open Spotlight search, type Disk Utility, and press Enter. Select your Mac’s system partition — generally “Macintosh HD.” Click the Verify Disk Permissions button if you’d like to check your permissions.
Disk Utility User Guide
Disk Utility can fix certain disk problems—for example, multiple apps quit unexpectedly, a file is corrupted, an external device doesn’t work properly, or your computer won’t start up. Disk Utility can’t detect or repair all problems that a disk may have.
If you run First Aid on a disk, Disk Utility checks the partition maps on the disk and performs some additional checks, and then checks each volume. If you run First Aid on a volume, Disk Utility verifies all the contents of that volume only.
In the Disk Utility app on your Mac, choose View > Show All Devices.
Note: If you’re checking your startup disk or startup volume, restart your computer in macOS Recovery, select Disk Utility in the macOS Utilities window, then click Continue. If you check your startup volume (Macintosh HD), make sure you also check your data volume (Macintosh HD - Data).
In the sidebar, select a disk or volume, then click the First Aid button .
If Disk Utility tells you the disk is about to fail, back up your data and replace the disk—you can’t repair it. Otherwise, continue to the next step.
Click Run, then click Continue.
If Disk Utility reports that the disk appears to be OK or has been repaired, you’re done. You can click Show Details to see more information about the repairs. Otherwise, you may need to do one of the following.
If Disk Utility reports “overlapped extent allocation” errors, two or more files occupy the same space on your disk, and at least one of them is likely to be corrupted. You need to check each file in the list of affected files. Most of the files in the list have aliases in a DamagedFiles folder at the top level of your disk.
If you can replace a file or re-create it, delete it.
If it contains information you need, open it and examine its data to make sure it hasn’t been corrupted.
If Disk Utility can’t repair your disk, or you receive a report that the First Aid process failed, try to repair the disk or partition again. If that doesn’t work, back up as much of your data as possible, reformat the disk, reinstall macOS, then restore your backed-up data.
If your Mac has a Fusion Drive and you see a flashing question mark or alert, see the troubleshooting section of the Apple Support article About Fusion Drive, a storage option for some Mac computers.
If you continue to have problems with your disk or it can’t be repaired, it may be physically damaged and need to be replaced. For information about servicing your Mac, see Find out how to service or repair your Mac.
What are disk permissions and why do they need repairing?
Disk permissions on macOS are used to keep your files secure. They’re designed so that certain programs (or other users if you share your Mac) can’t just dip into a system file they have no business with and modify it. They’d need permission to do that.
Every file and folder on your Mac comes with an associated set of permissions. From the Apple Community:
“Many things you install in Mac OS X are installed from package files (whose filename extension is '.pkg'). Each time something is installed from a package file, a 'Bill of Materials' file (whose filename extension is '.bom') is stored in the package's receipt file, which is kept in /Library/Receipts/ in Mac OS X v10.5 and earlier. These files don't take up much disk space and you shouldn't put them in the Trash. Each of those '.bom' files contains a list of the files installed by that package, and the proper permissions for each file.”
Unfortunately, these permissions can easily become messed up unintentionally. It’s quite common for this to happen when installing and uninstalling apps on your system. And when it does, apps can find themselves with free reign to alter files and modify read-only files which can cause all kinds of permission errors and system issues such as lagging, freezing, or crashing.
If you notice anything out of the norm regarding system performance, the first thing you should do is troubleshoot those disk permissions.
Below we’ll show you two ways: the manual and the easy one. Choose the way that works best for you.
How to repair permissions on Mac: The manual way
If you’re running an older version of macOS, Disk Utility is the go-to tool for troubleshooting problems.
Why an older version?
Because as of macOS version 10.11 El Capitan, Disk Utility no longer comes with the option 'repair disk permissions'. Boooo!
Apple even removed the command line:
But there’s a method to the madness. macOS now comes with a feature called System Integrity Performance (SIP) which is designed to automatically repair file permissions during software updates and system changes. SIP works by restricting the root account so that it can’t do things like modify protected locations and processes such as /System and /usr. This should prevent malware from gaining root permissions and infecting your system files.
Anyway, back to using Disk Utility to repair disk permissions. If you’re running a pre-El Capitan version of macOS, follow these steps:
1. Press Command + Space to open Spotlight, type in “Disk Utility”, and hit Enter.
2. Select Macintosh HD from the left sidebar menu.
Repair Disk Permissions Mac Sierra
3. Click on the First Aid tab.
4. Click on Verify Disk Permissions. By taking this step, Disk Utility will work through your hard drive to detect broken or misbehaving permissions and list them for repair. This might take a few minutes but you can check the Show details box to keep an eye on its progress.
5. Click on Repair Disk Permissions and wait while Disk Utility runs through the identified permissions to fix them.
If disk permission issues have played such havoc that your Mac won’t boot correctly, it’s possible to access Disk Utility in Recovery Mode. Do this by holding Command + R during bootup.
If you’re installing a newer (or older) version of macOS on top of your existing operating system, Mac will perform a disk permission repair as a part of the installation so that you start from a clean slate.
How to repair disk permissions on Mac: The easy way
For users of macOS versions El Capitan and newer, the removal of Repair Disk Permissions means you have no troubleshooting solution to turn to in if your Mac is ailing.
But worry not, CleanMyMac X is the hero you need.
CleanMyMac is like Disk Utility in that it does all of the heavy lifting for you to verify permissions and repair your Mac’s disk.
Even System Integrity Performance running quietly in the background doesn’t prevent certain issues from arising. If you’re suffering from any of the following problems, boot up CleanMyMac and have it take care of business:
- Improper functioning of applications.
- Inability to move or delete files.
- Inability to access files.
If you Mac appears to be running fine, it’s still worth running repairs every so often to ensure it stays that way. Not all broken permissions affect performance but that doesn’t mean they shouldn’t be fixed.
Repairing Disk Permissions in a few clicks
First things first, you’ll need to download CleanMyMac X. You can do that here. It’s free so you won’t need your credit card. Once that’s done, follow these five steps:
1. Launch CleanMyMac.
2. Click on Maintenance from the left sidebar menu.
3. Check the box next to Repair Disk Permissions.
4. Click Run.
Repair Disk Permissions Mac Os
CleanMyMac will scan your system to verify disk permissions and automatically repair permissions that are found to be faulty. When the task is complete, you’ll be able to view a log of all the permissions that were repaired.
And that’s all there is to it. Your Mac should now be running as intended.
Disk permissions are critical to your system’s security and performance but only when they’re working as they should. Use CleanMyMac to verify and repair disk permissions whenever you run into issues with apps or files for a healthy running Mac.
Repair Disk Permissions Mac App Free
Enjoy a clean, happy Mac!