How to Make Bootable MacOS Sierra 10.12 Beta USB Installer Drive

Many Mac users interested in installing MacOS Sierra Beta may prefer to do so with the assistance of a macOS Sierra 10.12 bootable installer USB drive, typically on a flash thumb drive or a similar disk. The advantages to this method is that the macOS Sierra installer is portable, it can be booted from, and it’s easy to perform a clean install or a partitioned dual boot situation with.

We’ll walk through exactly how to create a macOS Sierra 10.12 bootable install drive using the current Public Beta or Developer Beta preview release and a USB flash drive.

Requirements for Making Bootable MacOS 10.12 Install Disk
Before beginning, you will need the following:

• USB flash drive that you don’t mind formatting, this will become the bootable 10.12 Sierra installer drive (16GB or larger recommended, these are very cheap on Amazon)
• MacOS Sierra 10.12 Beta Installer application downloaded from the App Store / Developer Center or downloaded from Public Beta

The USB drive can be anything really, but the flash thumb drive is recommended due to ease. The MacOS Sierra installer application, labeled as “Install macOS Sierra.app”, “Install macOS Sierra Public Beta.app” or “Install 10.12 Developer Preview.app”, must reside in the /Applications/ folder, just like it does when you finish downloading it from the Mac App Store. Note that you’ll want to run through the bootable installer creation process before installing MacOS Sierra, because the installer application deletes itself once MacOS Sierra has completed installing. If you already ran the installer, you’d need to re-download MacOS Sierra and be sure it’s in /Applications/ folder.

Create a MacOS Sierra Bootable Installer Drive

1. Connect the USB drive to the Mac, remember this USB flash drive is going to be erased and formatted, so be sure nothing important is on that disk
2. Rename the USB flash drive to “SierraInstaller” without spaces (you can pick another name if desired, but you’d need to change the command syntax to accommodate)
3. Launch the Terminal application, located in /Applications/Utilities/ folder and issue the following command:

For MacOS Sierra 10.12 Final
sudo /Applications/Install macOS Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/SierraInstaller --applicationpath /Applications/Install macOS Sierra.app --nointeraction &&say Done

For MacOS Sierra 10.12 GM Build
sudo /Applications/Install macOS Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/SierraInstaller --applicationpath /Applications/Install macOS Sierra.app --nointeraction &&say Done

For MacOS Sierra 10.12 Developer Preview Beta
sudo /Applications/Install 10.12 Developer Preview.app/Contents/Resources/createinstallmedia --volume /Volumes/SierraInstaller --applicationpath /Applications/Install 10.12 Developer Preview.app --nointeraction &&say Done

For MacOS Sierra 10.12 Public Beta
sudo /Applications/Install macOS Sierra Public Beta.app/Contents/Resources/createinstallmedia --volume /Volumes/SierraInstaller --applicationpath /Applications/Install macOS Sierra Public Beta.app --nointeraction &&say Done

4. Double-check the syntax in Terminal for accuracy, then hit the Return key and authenticate with the admin password when requested, this starts the Sierra boot drive creation process and it can take a while to complete
5. The command line will update with various messages and progress, when the “Done” message appears, the MacOS Sierra Boot installer drive has been created successfully

“Erasing Disk: 0%… 10%… 20%… 30%…100%…
Copying installer files to disk…
Copy complete.
Making disk bootable…
Copying boot files…
Copy complete.
Done.”

6. Quit out of Terminal as usual when finished

It can take a while to complete the creation of the USB install drive, depending on the speed of the USB interface and the drive itself, so just be patient.

Once finished, you are free to update an existing installation to MacOS Sierra using the installer drive, or you can reboot any target Mac and hold down the “Option” key to select the macOS Sierra 10.12 installer as a bootable installation volume. Be sure the Mac you are trying to update is compatible with MacOS Sierra otherwise the installation will fail.

Proceed with the installation of macOS Sierra as any other Mac OS X system software installation, just be sure you back up a Mac first if you have personal data worth preserving.

That’s all there is to it. We’ll cover how to dual boot macOS Sierra Beta and other Mac OS X versions shortly. Remember that beta releases of system software are intended for advanced users and preferably on a secondary machine, beta software is notoriously buggy and tends to underperform compared to a regular final release.

Any questions? Tell us about your experience making a bootable macOS Sierra install drive in the comments below.