THE ULTIMATE GUIDE TO CREATING A BOOTABLE INSTALLER FOR macOS -

The Mac operating system is powerful, secure, and robust — but sometimes, you need more than just the default installation tools. Whether you’re deploying macOS across multiple devices, recovering a Mac that won’t boot, or preparing for a clean install, a bootable installer is the ultimate solution. In this guide, we walk you through the entireprocess of creating a macOS bootable USB installer — reliably, efficiently, and with the precision you expect from expert system documentation.

Do You Need a Bootable Installer?

Most users can reinstall or upgrade macOS directly via System Settings or macOS Recovery. However, in certain cases, a bootable installer offers key advantages:

Install macOS on multiple Macs without downloading the installer each time
Perform clean installations from scratch
Recover from startup issues when your internal disk isn’t bootable

Note: Creating a bootable installer is not the same as simply making an external startup disk.

Step 1 – Download the Full macOS Installer

You’ll need the full version of the macOS installer, not a stub or incremental update.

Where to Get It

Use the Mac App Store, or
Visit Apple’s support page: How to download and install macOS

Tips:

Download the installer on a compatible Mac (e.g. macOS Sequoia can only be downloaded on a Mac that supports it).
The installer should appear as an application in your /Applications folder — e.g. Install macOS Sequoia.app
If you download a .dmg or .pkg, follow Apple’s extra steps to extract the app.

Step 2 – Connect and Prepare a USB Flash Drive

Connect your USB stick (or external SSD) to your Mac.

Requirements:

Minimum 16GB (32GB recommended)
It will be completely erased, so back up any important files first

Rename the drive:

Use Disk Utility to rename your volume to:

MyVolume

This name is referenced in the Terminal command you’ll run in the next step.

Step 3 – Create the Bootable Installer Using Terminal

Open Terminal:

Finder > Applications > Utilities > Terminal

Paste the correct command based on your macOS version:

macOS Sequoia

sudo /Applications/Install\ macOS\ Sequoia.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolum

macOS Sonoma

sudo /Applications/Install\ macOS\ Sonoma.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume

macOS Ventura

sudo /Applications/Install\ macOS\ Ventura.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume

macOS Monterey

sudo /Applications/Install\ macOS\ Monterey.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume

macOS Big Sur

sudo /Applications/Install\ macOS\ Big\ Sur.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume

macOS Catalina

sudo /Applications/Install\ macOS\ Catalina.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume

macOS Mojave

sudo /Applications/Install\ macOS\ Mojave.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume

macOS High Sierra

sudo /Applications/Install\ macOS\ High\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume

OS X El Capitan

sudo /Applications/Install\ OS\ X\ El\ Capitan.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume --applicationpath /Applications/Install\ OS\ X\ El\ Capitan.app

Terminal Prompts and Behavior:

Type your administrator password when prompted (invisible input is normal).
Press Y to confirm erasing MyVolume.
Wait for the progress bar to complete.

Troubleshooting:

“Command not found” → Check the installer path and that it’s in /Applications
“Not a valid installer” → Delete and re-download the installer
Erase fails → Use Disk Utility to format MyVolume as Mac OS Extended (Journaled)

When successful, your USB drive will be renamed to something like: Install macOS Sequoia

Step 4 – Use the Bootable Installer

Mac with Apple Silicon (M1, M2, M3…)

Turn off the Mac completely
Plug in the USB installer
Press and hold the power button until startup options appear
Select the bootable installer and click Continue
Follow the onscreen macOS installation instructions

Intel-based Mac

Turn off the Mac
Plug in the USB installer
Power on and immediately press and hold the Option (⌥) key
Release when you see the bootable volumes
Select the installer and press Return
Choose Install macOS from the Utilities window

Important Notes

Mac must be connected to the internet
If macOS is incompatible, you may see a prohibited icon (circle with a line)
On Macs with a T2 Security Chip, allow external boot in Startup Security Utility

Conclusion: Take Full Control of Your macOS Installations

Creating a bootable macOS installer isn’t just for pros anymore. With just a USB stick and a few Terminal commands, you unlock a powerful tool for recovery, clean installs, or deploying macOS efficiently across multiple devices. Whether you’re a sysadmin or a power user, mastering this process gives you confidence and flexibility when it matters most.