Create a bootable installer drive
Roman Loyola explains how to put the macOS Mojave installer on an external drive and use it to install the OS on a Mac
Whenever Apple releases a new version of macOS, I like to create a bootable USB installation drive. I test different Macs, and when I need to upgrade those machines, it’s a lot more efficient to plug in the USB installer drive and run the installer, than to log into the App Store, download the 5GB OS installer, and then run it.
Because it’s so easy to create an external installation drive, it’s my preferred means of
installing the operating system. I keep it around for
those time when I would rather use the drive than
rely on booting in Recovery mode.
In this article I’ll go over the different ways you
can create a bootable macOS Mojave installation
drive. But before I give instructions on how to
create the drive, I’ll go over the items you’ll need
and how to get them.
Editor’s note: This tutorial was written using the
first version of the macOS Mojave Public Beta.
Get an external drive and an adaptor
The macOS Mojave Public Beta installer software is over 5GB. So you need a USB external drive that can hold that much data. The drive can be a thumb drive, hard drive, or SSD.
If you want to use a thumb drive, an 8GB drive works perfectly. I used an 8GB Kingston Data Traveler G4 (£5 from fave.co/2JvL8UY); it’s cheap and it supports USB 3.1, so it’s fast. I’ve also used a VisionTek 120GB USB 3.0 Pocket Solid State Drive (£109 from fave.co/2LspItE) and older USB thumb drives that support USB 2, which is slower, but works.
If you have a 2015 or newer MacBook or a 2016 or newer MacBook Pro, you may need Apple’s USB to USB-C adaptor (£19 from fave.co/2LsHOf9). This will allow you to connect a storage device that uses a USB type-A connector. If you don’t have an external drive and you have a USB-C Mac laptop, you could buy the SanDisk Ultra USB Type-C Flash Drive, which has a USB-C connector.
When creating the boot drive, the storage device is reformatted, so there’s no need to format the drive beforehand.
Get the macOS Mojave installer software
In order to get the Mojave installer, you need to sign up for the Apple Beta Software Program (tinyurl.com/pffuwnz). Once you’re enrolled, Apple will give you access to the Mojave installer in the App Store. If you launch the App Store app and look for it in the Updates section, you won’t find it.
Note that if you decide to participate in the Beta Software Program, there is a policy that Apple asks you to agree to. And keep in mind that this is beta software, so you could run into problems with the
OS and with the app that you use. You can read the information to learn more about Mojave. When you’re ready to download the software, click the Download button under the icon on the upper left. (If you’ve already downloaded the installer, the button will say Open instead of Download.)
Once the download is complete, the installer will launch automatically. But don’t continue with the installation. Instead, press Command-Q on your keyboard to quit the installer. The Mojave installer app will be in your Applications folder, so you can go there and launch it later to upgrade your Mac to the new operating system.
The quick way
I used a free app called Install Disk Creator (fave.co/2r6ZMf5) to make the installation drive.
There’s another app called DiskMaker X (fave.co/2HwhpuJ), but at the time of writing I wasn’t able to make it work with the Mojave Public Beta installer. Download Install Disk Creator by clicking on the link above. When the download is done, you can move it over to your Applications folder. Then follow these steps to create your bootable macOS Mojave drive.
1. Connect your drive to your Mac. It’s okay if it’s not formatted as a Mac drive. The app will reformat it.
2. Launch Install Disk Creator.
3. In the main window, you’ll see a pop-up menu under Select the volume to become the installer. Click on the menu and select your drive.
4. Under the pop-up menu, you’ll see Select the OS X installer. (macOS used to be called OS X.) If you have only the Mojave Beta installer on your Mac, Install Disk Creator will automatically select it. If you have other
macOS installers, you need to click on Select the OS X installer and select the Mojave installer.
5. When you’re ready, click Create installer. Your
Mac may tell you that Install Disk Creator wants
to make changes, and you need to enter your
username and password. After you do this, the app
will take a few minutes to create the boot drive. A
progress bar will appear at the bottom of the Install
Disk Create window. When the app is done, the
installer is ready to use.
The longer way using the Terminal
You don’t need to use Install Disk Creator to create a bootable installer. You can do it in the Terminal and it’s easy. Here are the instructions:
1. Connect the external drive to your Mac. In these
instructions, I use Untitled as the name of the
external drive. If your drive is named something
else, you need to change Untitled to the name
of your drive.
2. Launch Terminal (/Applications/Utilities/
3. Select and copy the following:
sudo /Applications/Install\ macOS\
createinstallmedia --volume /Volumes/
Untitled -- /Applications/Install\ macOS\
4. Go back to Terminal and paste the copied code at the prompt. Press Return.
5. Terminal will warn you that your external drive needs to be erased. To proceed, type Y at the prompt and press Return.
6. You’ll see that Terminal erases your drive and then copies the installer file to your drive. This will take a few minutes.
7. After copying, Terminal is done. You should see
Terminal display a ‘Copy complete’ and Done
notice. You can quit Terminal and your drive is
ready for use.
How to boot from the installer drive
1. Plug your external drive into your Mac.
2. Power up (or restart) your Mac. Press down on the Alt key while the Mac boots.
3. After a few moments, your Mac should display the Startup Manager, which will show you the available boot drives. Click on the external drive and press Return. (You don’t need to select a network to proceed.)
4. Your Mac will display a macOS Utilities window. If you want to install Mojave and leave the data intact, select Install macOS. If you want to start over and wipe out the data, you need to go into Disk Utility to reformat the internal drive first, and then install macOS Mojave.
A VisionTek USB drive connected to a 2017 MacBook Pro via Apple’s USB-C VGA Multiport Adapter (£69 from fave.co/2LtuCXh)
The main window of Install Disk Creator
Paste the code you copied into the Terminal then press Return. You’ll be asked about erasing the disk
The Terminal. Don’t worry if your screen doesn’t look like this. I changed it in the Terminal settings, and you can too. In Terminal, select Terminal > Preferences > Profiles, click on the one you like, and then click on the Default button