Creating a bootable MacOS Mojave beta installer drive with a USB key or flash drive is a common desire for many advanced Mac users testing the upcoming macOS 10.14 operating system.

Requirements to Make a macOS Mojave 10.14 Beta USB Install Drive

Before getting stated, you’ll need to meet a few simple requirements to be able to properly create a functioning macOS Mojave beta installer boot drive:

• A blank USB flash drive (16GB or larger is recommended), this will be erased to become the boot installer drive for macOS Mojave beta
• A Mac with internet access, and the Mac App Store
• The macOS Mojave 10.14 beta installer application downloaded in full from the Mac App Store and residing in the /Applications/ folder
• A Mac that is compatible with macOS Mojave
• Patience and some technical knowledge, with experience using the command line

Building a USB install drive for macOS Mojave beta requires using the command line, where exact syntax must be used in order to avoid erroneously erasing the wrong volume. Be sure to backup the Mac before beginning this process.

How to Make a Bootable macOS Mojave 10.14 Beta USB Installer Drive

• First, connect the USB flash drive to the Mac (if the USB flash drive is not yet formatted as MacOS Journaled Extended, do that first with Disk Utility)
• Download the macOS Mojave developer beta installer application from the Mac App Store
• When the macOS Mojave 10.14 beta installer has finished downloading it will automatically launch, quit out of the Mojave beta installer app, be sure to leave the “Install macOS 10.14 Beta.app” within the /Applications/ folder on the Mac
• Now open the “Terminal” application, found in /Applications/Utilities/ directory
• Enter the following command at the Terminal command line, replace “UNTITLED” with the USB drive name if necessary for your situation:

sudo /Applications/Install\ macOS\ 10.14\ Beta.app/Contents/Resources/createinstallmedia --volume /Volumes/UNTITLED && echo Mojave Drive Created

• Confirm the syntax is correct and hit the Return key and enter the administrator password as required by sudo
• The MacOS Mojave 10.14 beta installer drive will begin immediately, it can take a while to finish

After the macOS Mojave 10.14 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 Mojave beta installer to install the update, perform a clean install, or partition the Mac to install Mojave beta onto that partition instead. There are many options available for how to use the macOS Mojave beta install drive.

* If you are getting a “command not found” error, it’s likely that the syntax entered is incorrect, or the Install macOS 10.14 beta app installer is not downloaded and located within the /Applications directory.

Note this applies to the current macOS Mojave developer beta, we will update with instructions for the macOS Mojave public beta when it becomes available.

How to Boot from the macOS Mojave Beta USB Install Drive

• Connect the macOS Mojave 10.14 beta install drive to a Mac via USB if you have not done so already
• Reboot the Mac and hold down the OPTION key
• At the boot menu choose the macOS Mojave 10.14 beta installer volume to boot from

After you have booted from the macOS Mojave 10.14 beta USB drive, you can perform an installation of macOS Mojave beta, run Disk Utility to format or partition a drive, work with Time Machine, use the Terminal, or perform other common tasks from the bootable volume.

Once booted from the USB drive you can proceed with installing macOS High Sierra, using the Disk Utility tools to format or erase a volume, work with Time Machine, and other similar tasks. If you are aiming to install macOS Mojave beta onto a Mac, be sure the target Mac meets the macOS Mojave system requirements for compatibility.