How to Create a MacOS Catalina Beta USB Bootable Install Drive

Jun 6, 2019 - 5 Comments

How to make a MacOS Catalina beta bootable install drive

Advanced Mac users can make a bootable macOS Catalina beta installer drive using a USB flash drive. This offers a simple way to install the macOS 10.15 beta release onto a test Mac, either on a separate drive or partition.

Using a boot installer drive allows for easy formatting and partitioning of disks too, making it simple to perform a clean installation of macOS Catalina 10.15 beta onto a target Mac. Of course the boot installer can also be used to upgrade an existing installation to MacOS Catalina beta as well.

This tutorial will demonstrate how to create a bootable USB install drive for MacOS Catalina 10.15 beta.

Requirements to Make a macOS Catalina 10.15 Beta USB Installer Drive

You will need the following to be able to create a bootable installer drive for macOS Catalina beta:

We’re assuming you have some command line knowledge and understanding. Creating a bootable USB drive with this method requires using the Terminal, and syntax must be exact to avoid erroneously erasing the wrong drive. If you aren’t comfortable at the command line, it’s probably best to skip this.

How to Make a Bootable macOS Catalina 10.15 Beta USB Installer Drive

  1. Connect the USB flash drive to the Mac
  2. Open the “Terminal” application, found in /Applications/Utilities/ directory
  3. Enter the following command at the Terminal command line, replacing “UNTITLED” with the USB flash drive name of the device you want to turn into the bootable Catalina installer:
  4. sudo /Applications/Install\ macOS\ 10.15\ --volume /Volumes/UNTITLED && echo Catalina Boot Drive Created

  5. Confirm the syntax is correct, then hit the Enter/Return key
  6. Authenticate with the administrator password (this is necessary to use the sudo command)
  7. Let the installer creation process complete, it can take a little while

Once the MacOS Catalina 10.15 USB installer drive has been created, it can be used like any other boot disk on a Mac.

You can immediately run the installer from the MacOS Catalina 10.15 boot drive if you want to, otherwise you can use it to boot up any Mac that is compatible with MacOS Catalina.

Install macOS 10.15 Catalina beta splash screen

After the macOS Catalina 10.15 beta USB installer drive has finished being created, you can use it just like you would any other bootable Mac OS install drive. You can immediately run the installer, or eject the drive and use it on another Mac, or reboot the computer with it attached so that you can boot from the Catalina beta installer to install the update, perform a clean install, or partition the Mac to install Catalina beta onto that partition instead. There are many options available for how to use the macOS Catalina beta install drive.

Note that if you encounter a “command not found” error, it’s probably because of either a syntax error and you should check the command being run, or because the “Install macOS 10.15” application is not located in the /Applications folder as expected.

The above steps work for creating the macOS Catalina developer beta boot installer drive, typically the public beta has a differently named installer application and thus the command for making a bootable USB drive for macOS Catalina public beta will be slightly different. We’ll update that when it’s released and available.

How to Boot with macOS Catalina Beta USB Installer Drive

  • Connect the macOS Catalina 10.15 beta install drive to to the Mac you want to install Catalina onto
  • Reboot the Mac
  • Immediately hold down the OPTION key upon boot, keep holding Option until you see the boot menu
  • Choose the macOS Catalina 10.15 beta installer volume to boot from

How to boot from macOS Catalina 10.15 boot drive

After booting from the macOS Catalina installer drive, you’re free to format a target disk with Disk Utility, choose a disk to install macOS 10.15 onto, use Time Machine, access the Terminal from Recovery mode, and any other typical activity performed from a boot install drive.

Did you make a bootable macOS Catalina beta installer drive? Do you have another method to create a boot disk for macOS 10.15? Share your comments and experiences below!

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Posted by: Paul Horowitz in Mac OS X, Tips & Tricks


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  1. Michele Galvagno says:

    I would like to perform a direct install from the beta installer to an APFS formatted external SSD attached to my current MacBook Pro with Mojave so that I can have a sort of dual-boot for testing.

    How can I do this?
    Thank you

    • Sri says:

      That’s probably the best way to beta test macOS Catalina.

      You’re already halfway there it sounds like, format the external SSD as APFS, then when you launch the Catalina installer, target that external SSD as the installation destination.

      During system start you’ll then be able to hold OPTION to choose either Mojave (on the internal) or Catalina (on the external)

      Be sure you back up your entire Mac first, just in case something goes wrong. Then it’s easy to revert if needed.

  2. Fadi says:

    Can someone explain the following script

    ” sudo /Applications/Install\ macOS\ 10.15\ –volume /Volumes/UNTITLED && echo Catalina Boot Drive Created ”

    From what understood there has to be a command after “sudo” but since createinstallmedia is not installed we have to specify the fully path; /Applications/Install macOS 10.15

    Does the –volume option belong to “createinstallmedia” ?

    then i will create a volume in the Volumes directory.

    I know that && means if the left hand side is true then execute the right hand side.

    • Paul says:

      “createinstallmedia” is contained within the ‘Install macOS 10.15’ application which is located in the /Applications/ folder, so the command is specifying where to find the ‘createinstallmedia’ command.

      The — volume flag specifies where the target volume is located, that will be the USB flash drive. We’re assuming here it’s freshly formatted and named ‘UNTITLED’ which is the default of a freshly formatted drive from Disk Utility. You don’t need to create a volume, you simply need to connect a flash drive to the USB port that you don’t mind erasing and turning into the Catalina boot drive.

      And correct, && means if the aforementioned command has run, then echo that the boot drive has created.

      Hope that helps!

  3. Roman Tirler says:


    I am desperately trying to install 10.15 beta, following your procedure, however, i am stuck with error -9000F.

    I am running ing 10.14 mojave on the 2019 MBP.
    The external disk is a Samsung T5 SSD.

    What am I missing?

    Thanks, Roman

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