Note: If you need to create the USB from the recovery computer, you can copy the.iso to Macintosh HD and restore it to the USB drive with Disk Utility. Turn on your Mac and continue to hold the power button until you see the startup options window, which shows your bootable volumes and a gear icon labled Options. Select the volume containing the bootable installer, then click Continue. When the macOS installer opens, follow the onscreen instructions. A macOS Catalina USB install drive is a great tool to have on hand to for quick and easy macOS 10.15 reinstalls. We show you how in this video tutorial. For those who failed to create bootable USB with TransMac, take a look at UUByte DMG Editor. I managed to create two bootable USB from macOS Mojave and Catalina DMG file and successfully installed them on respect Mac. First, make sure the dmg file you downloaded is valid.

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.

What you need to create a bootable installer

  • A USB flash drive or other secondary volume formatted as Mac OS Extended, with at least 14GB of available storage
  • A downloaded installer for macOS Big Sur, Catalina, Mojave, High Sierra, or El Capitan

Download macOS

  • Download: macOS Big Sur, macOS Catalina, macOS Mojave, or macOS High Sierra
    These download to your Applications folder as an app named Install macOS [version name]. If the installer opens after downloading, quit it without continuing installation. 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.
  • Download: OS X El Capitan
    This downloads as a disk image named InstallMacOSX.dmg. 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.
  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 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.

Create Bootable Catalina Usb Mac Windows 10

Big Sur:*

Catalina:*

Mojave:*

Create Bootable Catalina Usb Mac

High Sierra:*

Apple support el capitan download. El Capitan:

Usb

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


After typing the command:

  1. Press Return to enter the command.
  2. When prompted, type your administrator password and press Return again. Terminal doesn't show any characters as you type your password.
  3. When prompted, type Y to confirm that you want to erase the volume, then press Return. Terminal shows the progress as the volume is erased.
  4. After the volume is erased, you may see an alert that Terminal would like to access files on a removable volume. Click OK to allow the copy to proceed.
  5. When Terminal says that it's done, the volume will have the same name as the installer you downloaded, such as Install macOS Big Sur. You can now quit Terminal and eject the volume.

Use the bootable installer

Determine whether you're using a Mac with Apple silicon, then follow the appropriate steps:

Apple silicon

Create Bootable Catalina Usb Mac Os

  1. Plug the bootable installer into a Mac that is connected to the internet and compatible with the version of macOS you're installing.
  2. Turn on your Mac and continue to hold the power button until you see the startup options window, which shows your bootable volumes and a gear icon labled Options.
  3. Select the volume containing the bootable installer, then click Continue.
  4. When the macOS installer opens, follow the onscreen instructions.

Create Bootable Usb Mac Catalina

Intel processor

Create Bootable Catalina Usb Mac Drive

  1. Plug the bootable installer into a Mac that is connected to the internet and compatible with the version of macOS you're installing.
  2. Press and hold the Option (Alt) ⌥ key immediately after turning on or restarting your Mac.
  3. Release the Option key when you see a dark screen showing your bootable volumes.
  4. Select the volume containing the bootable installer. Then click the up arrow or press Return.
    If you can't start up from the bootable installer, make sure that the External Boot setting in Startup Security Utility is set to allow booting from external media.
  5. Choose your language, if prompted.
  6. Select Install macOS (or Install OS X) from the Utilities window, then click Continue and follow the onscreen instructions.

Learn more

Create Bootable Usb Mac Disk Utility Catalina

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 the appropriate path in Terminal:

Create Bootable Catalina Usb Mac Download

  • Big Sur: /Applications/Install macOS Big Sur.app/Contents/Resources/createinstallmedia
  • Catalina: /Applications/Install macOS Catalina.app/Contents/Resources/createinstallmedia
  • Mojave: /Applications/Install macOS Mojave.app/Contents/Resources/createinstallmedia
  • High Sierra: /Applications/Install macOS High Sierra.app/Contents/Resources/createinstallmedia
  • El Capitan: /Applications/Install OS X El Capitan.app/Contents/Resources/createinstallmedia

A bootable installer doesn't download macOS from the internet, but it does require an internet connection to get firmware and other information specific to the Mac model.

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