How to Create a MacOS Catalina Beta USB 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:

• USB flash drive (16GB or larger) – this will be formatted to become the bootable install drive for macOS Catalina beta
• The full “Install macOS 10.15 Beta.app” installer application residing in the /Applications/ folder on the Mac (Download macOS Catalina developer beta if you have not done so already)
• A Mac that is connected to the internet, this is necessary to download the installer
• Mac compatible with MacOS Catalina

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:

For macOS Catalina FINAL version:
sudo /Applications/Install macOS Catalina.app/Contents/Resources/createinstallmedia --volume /Volumes/UNTITLED && echo Catalina Boot Drive Created

For macOS Catalina public beta:
sudo /Applications/Install macOS Catalina Beta.app/Contents/Resources/createinstallmedia --volume /Volumes/UNTITLED && echo Catalina Boot Drive Created

For macOS Catalina beta 2 and later:
sudo /Applications/Install macOS Catalina Beta.app/Contents/Resources/createinstallmedia --volume /Volumes/UNTITLED && echo Catalina Boot Drive Created

For macOS Catalina beta 1:
sudo /Applications/Install macOS 10.15 Beta.app/Contents/Resources/createinstallmedia --volume /Volumes/UNTITLED && echo Catalina Boot Drive Created

4. Confirm the syntax is correct, then hit the Enter/Return key
5. Authenticate with the administrator password (this is necessary to use the sudo command)
6. 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.

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 Beta.app” 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

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!