Create a bootable USB drive with Apple Mac OS X, including for downgrades

Create a Mac OS USB drive

A bootable macOS USB drive is one of the most practical tools when a Mac needs reinstalling, macOS Recovery does not work or a specific macOS version needs to be installed.

A USB installer can also help with a macOS downgrade. However, there is an important restriction: a Mac can generally only be used with a macOS version compatible with the particular Mac model. An operating system older than the version originally supported by the Mac normally cannot be installed.

In this updated guide, we show you step by step how to create a bootable macOS USB drive in 2026, including macOS Tahoe 26, macOS Sequoia 15, Sonoma 14, Ventura 13, Monterey 12 and older versions.

When does a bootable macOS USB drive make sense?

For a normal macOS update, you generally do not need a USB drive today. macOS can be installed directly through System Settings or macOS Recovery.

A bootable installer is still very practical, for example if:

• macOS no longer starts properly,
• macOS Recovery does not work,
• you want to perform a clean install,
• you want to install several Macs,
• you want to install a specific older macOS version,
• you want to return to an older compatible version after an update.

Which macOS versions exist?

Apple has changed the name of its operating system several times over the years. Mac OS X became OS X and later macOS.

What do you need for a bootable macOS drive?

You need:

• a compatible Mac,
• an internet connection to download macOS,
• the full macOS installer,
• a USB drive or external drive,
• administrator rights on the Mac.

Today, we recommend a USB drive with at least 32 GB. This ensures you are covered even for current macOS versions. A 64 GB drive offers some extra headroom and can easily be reused later.

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Download macOS directly from Apple

Where possible, use only installers directly from Apple. Downloads from unknown sources may have been modified or contain malware.

Current macOS versions

• macOS Tahoe 26: Download through Software Update or Terminal
• macOS Sequoia 15: Mac App Store
• macOS Sonoma 14: Mac App Store
• macOS Ventura 13: Mac App Store
• macOS Monterey 12: Mac App Store
• macOS Big Sur 11: Mac App Store
• macOS Catalina 10.15: Mac App Store
• macOS Mojave 10.14: Mac App Store
• macOS High Sierra 10.13: Mac App Store

Apple continues to provide corresponding downloads and information for even older versions.

All official macOS downloads from Apple

Download macOS through Terminal

A particularly practical option is downloading the full installer directly through Terminal.

Open Applications → Utilities → Terminal.

The following command shows which full macOS installers Apple currently offers for your Mac:

softwareupdate --list-full-installers

The actual download then follows this pattern:

softwareupdate --fetch-full-installer --full-installer-version VERSION

For example:

softwareupdate --fetch-full-installer --full-installer-version 26.1

or:

softwareupdate --fetch-full-installer --full-installer-version 15.7.2

Prepare the USB drive

Connect the USB drive directly to your Mac.

Caution: All data on the USB drive is erased during creation.

Apple uses the name MyVolume in its current guides. We therefore also use this name in the following Terminal commands.

1. Open Disk Utility.
2. Select the USB drive on the left.
3. Click Erase.
4. Assign the name MyVolume.
5. If necessary, choose Mac OS Extended (Journaled).
6. Confirm erasing.

Create a bootable macOS USB drive through Terminal

Once the downloaded installer is in the Applications folder, you can create the USB drive using Apple's built-in tool createinstallmedia.

macOS Tahoe 26

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

macOS Sequoia 15

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

macOS Sonoma 14

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

macOS Ventura 13

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

macOS Monterey 12

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

macOS Big Sur 11

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

macOS Catalina 10.15

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

macOS Mojave 10.14

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

macOS High Sierra 10.13

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

Run the Terminal command

Copy the appropriate command and paste it into Terminal.

After pressing Enter, macOS asks for your administrator password. While you enter the password, Terminal shows no characters or dots. This is normal.

Then, if necessary, confirm erasing the USB drive with:

Y

The drive is now erased and the macOS installer copied onto it.

When Terminal reports that the installation media is available, your bootable macOS drive is ready.

Start from the USB drive: Mac with an Apple chip

On current Macs with Apple chips, startup works differently from older Intel Macs.

1. Turn off the Mac completely.
2. Connect the bootable USB drive.
3. Hold down the power button.
4. Keep holding it until startup options appear.
5. Select the macOS installer.
6. Click Continue.

Start from the USB drive: Intel Mac

1. Turn off the Mac.
2. Connect the USB drive.
3. Turn on the Mac.
4. Immediately hold down the Option/Alt key (⌥).
5. Release the key when startup volumes appear.
6. Select the macOS installer.

Special case: Macs with the Apple T2 Security Chip

On certain Intel Macs with the Apple T2 Security Chip, starting from external media may be disabled.

In this case, open Startup Security Utility through macOS Recovery and allow starting from external or removable media.

macOS downgrade: can you install an older version?

A downgrade may be possible in principle, but not to just any macOS version.

What matters is which operating system versions your specific Mac model supports.

A downgrade normally requires erasing the existing system. Simply installing an older macOS version over a newer one generally does not work.

Perform a clean install or downgrade

1. Start the Mac from the USB installer.
2. Disk Utility — open this.
3. View → Show All Devices — select this.
4. Select the internal SSD or the desired volume.
5. Click Erase.
6. Close Disk Utility.
7. Install macOS — select this.
8. Select the desired installation destination.

Which file system should be used?

On modern macOS versions and SSDs, APFS is the usual file system.

On older macOS versions, however, Mac OS Extended (Journaled) may be required.

Error: “command not found”

If Terminal reports that the command was not found, first check that the full installer is actually in the Applications folder.

For Tahoe, for example, the following app must be present:

/Applications/Install macOS Tahoe.app

Error: the desired macOS installer is not displayed

First check with the following Terminal command which full installers Apple offers for your Mac:

softwareupdate --list-full-installers

If the desired version is not displayed, it may be unavailable or incompatible with the Mac being used.

Can I use a macOS USB drive for several Macs?

Yes. A bootable macOS installer can generally be used for several compatible Macs.

However, each Mac must be compatible with the macOS version on the drive.

Do not turn off the Mac during installation

During a macOS installation, the Mac may restart several times. The screen may temporarily stay black and it can appear that nothing is happening.

Do not turn off the Mac during this process.

On a MacBook, the power adapter should remain connected throughout the installation.

Bootable macOS drive in 2026: conclusion

Although Apple has considerably simplified macOS Recovery and resetting modern Macs, a bootable USB drive remains a useful tool for repairs, clean installs and certain downgrades.

Particularly practical is the combination of:

• softwareupdate --list-full-installers to display available macOS versions,
• softwareupdate --fetch-full-installer to download the installer, and
• createinstallmedia to create the bootable USB drive.

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Official Apple guide

Note: Installing or erasing an operating system is performed at your own responsibility. Always check your Mac model's compatibility before installation and create a complete backup of important data.