How to create a bootable installer using Terminal. Plug the USB stick, hard drive or SSD into your Mac. Go to ApplicationsUtilities and double-click Disk Utility to launch it. Select the disk you want to use for the installer and choose the Erase tab. Because the macOS installer application is an.app file and do not arrive as a disk image, to create a MacOS ISO file requires a sequence of steps through the command line, or the use of a third party application. For the purposes here, we’ll walk through how you can make a MacOS Big Sur ISO file by using the terminal.
Curious about how to create a bootable installer for macOS? It might sound like a lot of manual work, but It's not as daunting as it sounds. In this article, we'll take a closer look at all the necessary steps, plus some bonus tips.
Knowing how to create a bootable installer for macOS is handy if you want to install the newest macOS version across multiple Macs, install the latest macOS beta, or carry out a clean install.
All you need is a macOS formatted USB, HDD, or SSD. So let's get started.
To put it simply, a bootable USB for Mac is a portable device that contains all the required installation files for a particular version of macOS. It will enable you to boot your Mac from the file system within the flash drive instead of your hard drive.
First things first, before we go any further, let's take a look at what you need to create a bootable macOS Monterey installer:
USB, HDD, or SSD with at least 16GB of available memory.
Make sure the portable device is formatted for macOS.
Before you start reformatting and erasing disks, it's worth doing a backup to protect all of your files, just if something happens, goes wrong, or you want to revert back. Here's how to back up your Mac with Time Machine:
Open the Apple Menu > System Preferences > Time Machine.
Click Select Disk and locate your preferred location; select Use Disk.
Time Machine will now begin making a backup.
Before you create a bootable installer, it’s wise to give your machine a quick cleanup, so it's fully optimized and running its best before you upgrade its system.
You could spend time clearing out cache, junk and locating all of your temporary system logs manually, or you could save valuable time with a tool like CleanMyMac X. That's what I like to do: it's quick, easy, and notarized by Apple.
Launch the app — download the free version here.
Select System Junk from the sidebar.
Once complete, press Clean.
Now you're finally ready to start, let's create a bootable USB mac.
Download macOS Monterey installer from the official Apple support site.
Once complete, the installer will launch, do not select the Continue button. Instead, quit by pressing Command-Q.
Open your Applications folder and locate the 'Install macOS Monterey' app.
Confirm that the installer is located in your Applications folder. If it's not, use Finder to search for it and move it to the Applications. This is an essential step for the setup a little later.
Now let's create a bootable installer for macOS. Here's how:
The first phase is to erase your USB Drive ready for the Monterey installer.
Plug in your external drive.
Launch Disk Utility (press Command-Space, then type Disk Utility).
From the left sidebar, select the root drive of your external device and press Erase.
Be sure to choose the following: Name - MyVolume; Scheme - GUID Partition Map; Format - Mac OS Extended (Journaled).
Select Erase, and wait for the setup to complete, and press Done.
The second phase is to install the Monterey installer onto your external drive using the 'createinstallmedia' command in Terminal; here's how:
Ensure that your external drive is connected, and open Terminal (press Command-Space and type Terminal).
Paste the below command and press Enter.
sudo /Applications/Install macOS Monterey.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume
(This command assumes that the installer is in your Applications folder like we checked for earlier and that MyVolume is the name of the USB drive like we entered in the previous steps.)
If prompted, type your admin password, then press Enter again. (Terminal doesn't show characters when you type your password)
Type Y to confirm volume erase, press Enter, wait for this to complete, and press OK to enable the copy.
When Terminal says that it's done, notice that the volume has the same name as the installer, quit Terminal, and eject the volume.
So now you've made your USB bootable installer, you can use it on multiple compatible devices to install macOS; here's how:
When the installation is complete, your Mac will reboot with the new macOS version. Congratulations, you just successfully did a MacBook boot from USB.
So we've reached the end of this article; now you know how to create a macOS Monterey installer along with how to get your Mac prepared and what you'll need to create a bootable installer for macOS. Come back soon for more useful tips and tricks!
These advanced steps are primarily for system administrators and others who are familiar with the command line. You don't need a bootable installer to upgrade macOS or reinstall macOS, but it can be useful when you want to install on multiple computers without downloading the installer each time.
MyVolumein these commands with the name of your volume.
* If your Mac is using macOS Sierra or earlier, include the
--applicationpath argument and installer path, similar to the way this is done in the command for El Capitan.
After typing the command:
Yto confirm that you want to erase the volume, then press Return. Terminal shows the progress as the volume is erased.
Determine whether you're using a Mac with Apple silicon, then follow the appropriate steps:
A bootable installer doesn't download macOS from the internet, but it does require an internet connection to get firmware and other information specific to the Mac model.
For information about the
createinstallmedia command and the arguments you can use with it, make sure that the macOS installer is in your Applications folder, then enter the appropriate path in Terminal: