How to Create a Bootable USB macOS Installer: Step-by-Step Guide

Creating a bootable USB macOS installer can be a game-changer for anyone who uses a Mac regularly. Whether you’re looking to perform a clean install of macOS, troubleshoot a system, or install macOS on multiple Macs, having a bootable USB installer offers flexibility and control. In this guide, we’ll show you how to create a bootable macOS USB installer using the createinstallmedia command in Terminal.

Having a bootable USB drive means you can reinstall macOS without needing an internet connection, and it can also save you valuable time if you need to install macOS on multiple devices. Instead of downloading the installer repeatedly, you can use the same USB to install macOS on several machines, making it an efficient solution for IT professionals, businesses, and even home users.

The process may sound intimidating at first, but it’s simpler than you might think. With the correct macOS installer file, a USB drive, and a few commands, you’ll be ready to go. This guide covers everything from what you need to how to boot from the USB drive once it’s ready.

Why Create a Bootable macOS USB Installer?

There are multiple reasons why creating a bootable macOS USB installer is advantageous.

• Clean Installations: If your Mac is running slow, has persistent software issues, or you simply want a fresh start, a clean installation of macOS is often the best solution. A bootable USB allows you to wipe your hard drive and install a fresh copy of the OS.
• Install macOS on Multiple Macs: Rather than downloading a multi-gigabyte macOS installer on every machine, a bootable USB lets you install macOS on several Macs quickly and efficiently.
• System Recovery: If your Mac won’t boot or you’re unable to access Recovery mode, the bootable USB is a great backup for system recovery.
• Downgrade macOS: If a new update is causing issues, you can use the bootable installer to revert to a previous macOS version.
• Unsupported Hardware: For older Intel-based Macs no longer supported by Apple, a bootable USB is often the only way to install newer macOS versions using tools like OpenCore Legacy Patcher.

A bootable macOS USB installer is invaluable in scenarios where standard updates or built-in Recovery modes aren’t sufficient.

What You Need to Create a Bootable USB for macOS

Here’s a list of everything you’ll need to create your bootable macOS installer:

• A USB Drive (32GB or Larger): You’ll need a USB drive or external drive with at least 32GB of space. It’s a good idea to use a USB 3.0 or Thunderbolt drive for faster speeds, especially when using newer M-series Macs.
• macOS Installer: Download the macOS installer from the Mac App Store or via Software Update in System Preferences. Ensure you don’t start the installation process, as this will erase the installer files.
• A Mac: You need a Mac running macOS 10.7 Lion or later to create the bootable USB.
• Admin Access: You’ll need an administrator account to use Terminal and execute the necessary commands.
• Internet Access: While creating the installer, you’ll need an internet connection to download macOS and ensure the process runs smoothly.

Step-by-Step Guide to Create a Bootable macOS Installer

1. Download the macOS Installer
   Go to the Mac App Store and search for the version of macOS you want to install. Once you find it, click Download. Wait for the installer to finish downloading, but don’t allow the installation to begin. The installer files will be located in your Applications folder.
2. Prepare the USB Drive
   Insert your USB drive into the Mac.

• Open Disk Utility (Command + Space, then type “Disk Utility”).
• Select the USB drive and click Erase.
• Choose APFS as the format (for macOS Big Sur or later) or Mac OS Extended (Journaled) (for macOS Catalina or earlier).
• Select GUID Partition Map as the scheme.
• After choosing the name for the drive, click Erase.

3. Use the createinstallmedia Command
   Once the drive is prepared, it’s time to create the bootable installer using the createinstallmedia command in Terminal.

• Open Terminal (Command + Space, then type “Terminal”).
• Enter the appropriate command for the macOS version you are installing. For example, to create a bootable installer for macOS Sonoma, use: sudo /Applications/Install\ macOS\ Sonoma.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume Replace “MyVolume” with the name of your USB drive.
• Press Return, and when prompted, enter your password (the characters won’t appear in Terminal).
• Confirm by typing Y when asked to erase the drive.

The command will erase your USB drive and copy the installer files. This can take several minutes, so be patient. Once finished, Terminal will show “Copy complete. Done.”

4. Boot From the Installer
   To boot from the USB drive, follow these steps:

• For Apple Silicon Macs: Shut down the Mac, press and hold the power button until Startup Options appear, then select the USB drive.
• For Intel-based Macs: Shut down the Mac, turn it on, and immediately hold the Option (Alt) key to bring up the boot menu. Select the USB drive to begin the installation.

Createinstallmedia Commands for Different macOS Versions

• macOS Tahoe: sudo /Applications/Install\ macOS\ Tahoe.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume
• macOS Sequoia: sudo /Applications/Install\ macOS\ Sequoia.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

Choose the command that matches the macOS version you want to install.

Conclusion

A bootable macOS USB installer is an essential tool for any Mac user. It gives you control over your system’s installation and recovery process, making it easier to perform clean installs, troubleshoot, or install macOS on multiple Macs. By following the simple steps in this guide, you can create a bootable installer using the Terminal’s createinstallmedia command, and it will work on both Intel-based Macs and newer Apple silicon models.