What does repairing permissions do

Tom is also president of Coyote Moon, Inc. Disk Utility is versatile and erase, format, partition, and work with disk images. It's also the first line of defense when it comes to verifying whether a drive is working correctly, and it repairs drives that exhibit other types of problems, including those that cause a Mac to fail during startup or freeze while being used. Disk Utility has evolved, gaining new features with each new version of OS X.

For the most part, Apple added features and capabilities to the original Disk Utility core app. While it retains the same name, its user interface underwent a dramatic makeover.

Therefore, there are two separate workflows for using Disk Utility's First Aid feature. If you use macOS Catalina If you're using OS X Yosemite or earlier, you're right where you need to be.

One repairs a hard drive, while the other repairs file and folder permissions. Disk Utility can repair common disk issues, ranging from corrupt directory entries to files left in unknown states, usually from power outages, forced restarts, or forced application quits. Disk Utility's Repair Disk feature is excellent for making minor disk repairs to a volume's file system, and it can make most repairs to a drive's directory structure. Still, it's no substitute for a backup strategy. The Repair Disk feature is not as robust as some third-party applications that recover files, something Repair Disk is not designed to do.

Disk Utility's Repair Disk Permissions feature is designed to restore file or folder permissions to the state the OS and applications expect. Permissions are flags set for each item in the file system. They define whether an item can be read, written to, or executed.

Permissions are initially set when an application or group of files is installed. The installation includes a. Repair Disk Permissions uses the. Disk Utility's Repair Disk feature can work with any drive connected to your Mac, except the startup disk.

If you select the startup disk, the Repair Disk tab is grayed out. If the permissions were changed to any of these files or folders, you can expect a multitude of bizarre of problems on your Mac.

Issues that can arise due to incorrect permissions include:. From the Finder sidebar, right-click your Home folder and choose Get Info. Click the Lock button at the bottom of the window and enter your administrator password.

Then select the action menu button and choose Apply to enclosed items. Click OK to confirm the action. The updated permissions will propagate through your Home folder. If everything goes well, reboot your Mac. The steps for Mojave and newer are the same as the above, but you must add Terminal to Full Disk Access before proceeding.

Click the Lock icon and enter your administrator password to make changes. Next, select the Full Disk Access tab. Then click the Plus button and add the Terminal app. That means regular checks of your drive can prevent more serious problems, including data loss, down the road. This is especially true in Mac OS X In a word, no. The only real benefit to repairing permissions before a Mac OS X update is that if you do so, then immediately install the update, and then repair permissions again immediately afterwards, you can be pretty confident that any permissions issues that are found are a result of the update.

Unless a problem occurs with the installation, the permissions outlined in the receipt s will match the permissions on the actual files that have been installed; in other words, no repairs will be necessary. A quick Repair Disk Permissions, and I was good to go. But these are the exceptions, not the rule—the vast majority of users will be fine repairing permissions only after they experience a problem.

I asked Apple that very question; the company declined to comment. Critics of frequent permissions repairs claim that the procedure can actually do more harm than good by resetting permissions that have been changed from their defaults—presumably for good reason—by the user, an application, or an installer. What about more advanced users who intentionally change permissions on system-level files—clearly an unsupported procedure—in order to modify the system in some way?

The fact that these advanced users and software products exist is hardly a convincing argument against your typical Mac user repairing permissions, even frequently. And remember to keep this risk in perspective: A very small minority of users tweaking system-level Apple components that also happen to be affected by the Repair Disk Permissions function.

But you can also use the Repair Disk Permissions function while booted from the disc to ensure that system-level file permissions are correct. A similar solution can be found in the free AppleJack ; August , a third-party maintenance and troubleshooting utility. Given that you can access a shell at startup via single-user mode , and that I previously showed you the command for repairing permissions via Terminal, you might think that you could repair permissions in single-user mode using that command.

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