How to use Disk Utility on a Mac

How to use Disk Utility on a Mac

Disk Utility is an app that comes with your Mac. Its tucked away in the Utilities folder, which is found inside the Applications folder, but is easy to locate using Spotlight which you trigger by pressing Command+Space Bar. Heres what you can use Disk Utility for: Disk Utility was overhauled in Mac OS X El Capitan when it got a redesign and many of the features evolved or were removed. There are also a few changes in macOS High Sierra thanks to the new file format Apple has introduced: APFS (more on that below).

You might want to use Disk Utility it if you experience the following: Your computer wont start up. (Read: An external device wont work. (Read: If you think there is a problem with the drive inside your Mac or an external storage device, you can use the First Aid feature in Disk Utility to check. The First Aid feature in Disk Utility will run various checks and if it detects an issue with your disk it will repair it. Note: Disk Utility had a bit of a makeover in OS X El Capitan and as a result the way that you repair a disk has changed slightly.

The steps you need to take will depend on the version of MacOS you are running. Were going to assume you are running a version that is newer than El Capitan since that version of Mac OS X launched in September 2015. Heres how to run First Aid on your Mac to check if there is a problem with your disk: If it finds a problem with the disk, Disk Utility will attempt to repair it. If Disk Utility tells you the disk or volume is about to fail, you should back it up and replace it. Disk Utility will not be able to repair it.

If Disk Utility reports that the disk is OK that means there isnt a problem with the disk. How you repair a disk depends whether its your Mac's Startup Disk (the disk that you Mac runs from, where the operating system is installed), or a separate disk that's plugged into your Mac. If its your Startup Disk jump to the next section. If Disk Utility is unable to repair the drive, or it believes that the disk is about to fail it will warn you.

Should this be the case you should back up your data before its too late. Read this article on You may also find this useful: . You can run First Aid on your startup drive as above, but if Disk Utility finds any errors it wont attempt to fix them. If you need to repair your Macs startup drive (the boot volume) you won't be able to as Disk Utility cant repair the mounted volume (the one that everything is running from). In older versions of Disk Utility you will see that the Repair Disk option is greyed out. In this case you need to start up your Mac in Recovery Mode and repair the disk from there. This way things can run from the Recovery HD volume that was created when MacOS was installed. (Note if you have a Fusion Drive things are even more complex).

When Apple released El Capitan in 2015 it removed the ability to repairing disk permissions. The removal of the feature probably indicates that repairing permissions didnt really do a whole lot of good. It is still possible to repair permissions using Terminal, but we wont go into that here, following Apples lead and assuming that it wont do any good and might actually cause more issues. However, if you are using Mac OS X Yosemite or earlier, and a file's permissions are no longer set correctly, software that uses the file might not work correctly.

If thats the case, heres how to fix permissions: Disk Utility is able to create a disk image of contents of a folder which you can then transfer to another Mac, an archive, or any location that doesnt accept folders. Its similar to compressing the folder into a zip archive, but the benefit is that you can not only use disk image compression to save space, but can also take advantage of Apples encryption for the disk image. .

There are a number of reasons why you might want to format a drive. Perhaps you want to wipe your startup drive so you can perform a fresh install of OS X, maybe you want to encrypt an external storage drive that you use for work, or you might wish to create a partition for Windows or a different version of the Mac operating system.

We have a step by step . Here's what to do if you plug a hard drive or flash drive in to your Mac and doesn't see it and won't let you access the data: You may wish to partition a disk if you want to install multiple operating systems. How you partition will depend on whether you are running High Sierra or an earlier version of macOS or Mac OS X. Theres more : We have a .