Disk For Mac

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Erasing your disk: For most reasons to erase, including when reformatting a disk or selling, giving away or trading in your Mac, you should erase your entire disk.

Dec 29, 2015 Connect the drive to the Mac. Open Disk Utility. The easiest way to do that is hit CMD and the spacebar at the same time and type in Disk Utility to find the program. Jul 02, 2020 How to erase your disk. Start up from macOS Recovery. Then select Disk Utility from the Utilities window and click Continue. If you're not erasing the disk your Mac. Choose View Show All Devices from the menu bar in Disk Utility. The sidebar now shows your disks (devices) and any containers. Important If you start Classic after installing Mac OS X, Classic installs this version of Startup Disk in the Mac OS 9.1 System Folder it uses. Best VPN Services for 2020. Active@ KillDisk for Mac is an easy-to use & compact freeware utility that allows to sanitize attached media storage with the 24 international data sanitizing standards. It permanently erases all data on Hard Disks, Solid State Drives, Memory Cards & USB drives, SCSI storage & RAID disk arrays. Freeware version installation package (dmg) includes executable, being able to run on iMac, MacBook & Mac Pro family and erase all attached disks except the system disk with One Pass Zeros data. Important If you start Classic after installing Mac OS X, Classic installs this version of Startup Disk in the Mac OS 9.1 System Folder it uses. Best VPN Services for 2020.

Erasing a volume on your disk: In other cases, such as when your disk contains multiple volumes (or partitions) and you don't want to erase them all, you can erase specific volumes on the disk.

Erasing a disk or volume permanently deletes all of its files. Before continuing, make sure that you have a backup of any files that you want to keep.

How to erase your disk

  1. Start up from macOS Recovery. Then select Disk Utility from the Utilities window and click Continue.
    If you're not erasing the disk your Mac started up from, you don't need to start up from macOS Recovery. Just open Disk Utility from the Utilities folder of your Applications folder.
  2. Choose View > Show All Devices from the menu bar in Disk Utility. The sidebar now shows your disks (devices), and any containers and volumes within them. The disk your Mac started up from will be at the top of the list. In this example, Apple SSD is the startup disk:
  3. Select the disk that you want to erase. Can't see your disk?
  4. Click Erase, then complete these items:
    • Name: Type the name you want the disk to have after you have erased it.
    • Format: Choose APFS or Mac OS Extended (Journalled). Disk Utility shows a compatible format by default.
    • Scheme: Choose GUID Partition Map.
  5. Click Erase to start erasing your disk, and every container and volume within it. You may be asked to enter your Apple ID. Forgotten your Apple ID?
  6. When it's finished, quit Disk Utility.
  7. If you want your Mac to be able to start up from the disk you erased, reinstall macOS on the disk.

How to erase a volume on your disk

  1. Start up from macOS Recovery. Then select Disk Utility from the Utilities window and click Continue.
    If you're not erasing the volume your Mac started up from, you don't need to start up from macOS Recovery. Just open Disk Utility from the Utilities folder of your Applications folder.
  2. In the sidebar of Disk Utility, select the volume that you want to erase. The volume your Mac started up from will be called Macintosh HD, unless you have changed its name. Can't see your volume?
  3. Click Erase, then complete these items:
    • Name: Type the name you want the volume to have after you have erased it.
    • Format: Choose APFS or Mac OS Extended (Journalled). Disk Utility shows a compatible format by default.
  4. If you see an Erase Volume Group button, the volume you have selected is part of a volume group. In that case, you should erase the volume group. Otherwise, click Erase to erase just the selected volume. You may be asked to enter your Apple ID. Forgotten your Apple ID?
  5. When it's finished, quit Disk Utility.
  6. If you want your Mac to be able to start up from the volume you erased, reinstall macOS on that volume.

Reasons to erase

You can erase at any time, including in circumstances such as these:

  • You want to permanently erase all the content from your Mac and restore it to factory settings. This is one of the final steps before selling, giving away or trading in your Mac.
  • You’re changing the format of a disk, such as from a PC format (FAT, ExFAT or NTFS) to a Mac format (APFS or Mac OS Extended).
  • You’ve received a message that your disk isn’t readable by this computer.
  • You're trying to resolve a disk issue that Disk Utility can't repair.
  • The macOS installer doesn’t see your disk or can’t install on it. For example, the installer might say that your disk isn’t formatted correctly, isn’t using a GUID partition scheme, contains a newer version of the operating system or can’t be used to start up your computer.
  • The macOS installer says that you may not install to this volume because it is part of an Apple RAID.
Disk For Mac

About APFS and Mac OS Extended

Disk Utility in macOS High Sierra or later can erase using either the newer APFS (Apple File System) format or the older Mac OS Extended format, and it automatically chooses a compatible format for you.

How to choose between APFS and Mac OS Extended

Disk Utility tries to detect the type of storage and show the appropriate format in the Format menu. If it can’t, it chooses Mac OS Extended, which works with all versions of macOS. If you want to change the format, answer these questions:

  • Are you formatting the disk that came built into your Mac?
    If the built-in disk came APFS-formatted, Disk Utility suggests APFS. Don't change it to Mac OS Extended.
  • Are you about to install macOS High Sierra or later for the first time on the disk?
    If you need to erase your disk before installing High Sierra or later for the first time on that disk, choose Mac OS Extended (Journaled). During installation, the macOS installer decides whether to automatically convert to APFS — without erasing your files.
  • Are you preparing a Time Machine backup disk or bootable installer?
    Choose Mac OS Extended (Journalled) for any disk that you plan to use as a Time Machine backup disk or as a bootable installer.
  • Will you be using the disk with another Mac?
    If the other Mac isn't using macOS High Sierra or later, choose Mac OS Extended (Journalled). Earlier versions of macOS won't work with APFS-formatted volumes.

How to identify the format currently being used

If you want to know which format is currently in use, use any of these methods:

  • Select the volume in the Disk Utility sidebar, then check the information shown on the right. For more detail, choose File > Get Info from the Disk Utility menu bar.
  • Open System Information and select Storage in the sidebar. The File System column on the right shows the format of each volume.
  • Select the volume in the Finder, then choose File > Get Info from the menu bar. The Get Info window shows the Format of that volume.
Disk For Mac

If your disk or volume doesn't appear or the erase process fails

  1. Shut down your Mac, then unplug all non-essential devices from your Mac.
  2. If you're erasing an external drive, make sure it's connected directly to your Mac using a cable that you know is in good working order. Then turn the drive off and back on.
  3. If your disk or volume still doesn't appear in Disk Utility or Disk Utility reports that the erase process failed, your disk or Mac may need a service. If you need help, please contact Apple Support.

Learn more

  • If you can't start up from macOS Recovery, you can use a different startup disk instead.
  • If Disk Utility shows a Security Options button in the Erase window, you can click that button to choose between a faster (but less secure) erase and a slower (but more secure) erase. Some older versions of Disk Utility offer the option to zero all data instead. These secure-erase options aren't offered or needed for solid-state drives (SSDs) and flash storage.

These advanced steps are primarily for system administrators and others who are familiar with the command line. You don't need a bootable installer to upgrade macOS or reinstall macOS, but it can be useful when you want to install on multiple computers without downloading the installer each time.

Download macOS

Find the appropriate download link in the upgrade instructions for each macOS version:

macOS Catalina, macOS Mojave, ormacOS High Sierra
Installers for each of these macOS versions download directly to your Applications folder as an app named Install macOS Catalina, Install macOS Mojave, or Install macOS High Sierra. If the installer opens after downloading, quit it without continuing installation. Important: To get the correct installer, download from a Mac that is using macOS Sierra 10.12.5 or later, or El Capitan 10.11.6. Enterprise administrators, please download from Apple, not a locally hosted software-update server.

OS X El Capitan
El Capitan downloads as a disk image. On a Mac that is compatible with El Capitan, open the disk image and run the installer within, named InstallMacOSX.pkg. It installs an app named Install OS X El Capitan into your Applications folder. You will create the bootable installer from this app, not from the disk image or .pkg installer.

Use the 'createinstallmedia' command in Terminal

  1. Connect the USB flash drive or other volume that you're using for the bootable installer. Make sure that it has at least 12GB of available storage and is formatted as Mac OS Extended.
  2. Open Terminal, which is in the Utilities folder of your Applications folder.
  3. Type or paste one of the following commands in Terminal. These assume that the installer is still in your Applications folder, and MyVolume is the name of the USB flash drive or other volume you're using. If it has a different name, replace MyVolume in these commands with the name of your volume.
    Catalina:*
    Mojave:*

    High Sierra:*
    El Capitan:
  4. Press Return after typing the command.
  5. When prompted, type your administrator password and press Return again. Terminal doesn't show any characters as you type your password.
  6. When prompted, type Y to confirm that you want to erase the volume, then press Return. Terminal shows the progress as the bootable installer is created.
  7. When Terminal says that it's done, the volume will have the same name as the installer you downloaded, such as Install macOS Catalina. You can now quit Terminal and eject the volume.
Disk For Mac

* If your Mac is using macOS Sierra or earlier, include the --applicationpath argument, similar to the way this argument is used in the command for El Capitan.

Disk For Mac

Use the bootable installer

After creating the bootable installer, follow these steps to use it:

  1. Plug the bootable installer into a compatible Mac.
  2. Use Startup Manager or Startup Disk preferences to select the bootable installer as the startup disk, then start up from it. Your Mac will start up to macOS Recovery.
    Learn about selecting a startup disk, including what to do if your Mac doesn't start up from it.
  3. Choose your language, if prompted.
  4. A bootable installer doesn't download macOS from the Internet, but it does require the Internet to get information specific to your Mac model, such as firmware updates. If you need to connect to a Wi-Fi network, use the Wi-Fi menu in the menu bar.
  5. Select Install macOS (or Install OS X) from the Utilities window, then click Continue and follow the onscreen instructions.

Learn more

For more information about the createinstallmedia command and the arguments that you can use with it, make sure that the macOS installer is in your Applications folder, then enter this path in Terminal:

Disk

Catalina:

Apple Disk Utility Download

Mojave:

Disk For Macbook Pro

High Sierra:

Mac Disk Utility For Windows

El Capitan: