How to create a macOS Sequoia installer for a clean installation

Creating a USB installer for macOS Sequoia is a very useful resource if you need to install the operating system on multiple computers or without relying on an internet connection. This method is especially useful for performing a clean installation of Apple’s new operating system. Let’s take a look at how to create a macOS Sequoia installer in just four steps.

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Step 1: Select the appropriate USB device

To begin, we will need a USB flash drive with a minimum capacity of 16 GB, although it’s recommended that you use a 32 GB drive (or greater) to ensure enough space. It’s important that the drive is empty or doesn’t contain any data that you wouldn’t want to lose, because this process will erase everything on the flash drive.

Step 2: Download the macOS Sequoia installer

The macOS installer can be obtained directly from the Terminal application on your Mac. Open the application by searching for “Terminal” in Spotlight and paste (or type) the following command:

softwareupdate --list-full-installers

Then, you will search for the latest macOS Sequoia installer and download it using the following command, replacing 15.0 with the latest version, if necessary:

softwareupdate --fetch-full-installer --full-installer-version 15.0

This step will download the installer to your Applications folder.

Step 3: Connect the USB drive

Connect the USB to your computer and open the Disk Utility application, located in Applications > Utilities > Disk Utility. Once there, select the drive in the left sidebar and click on Erase. Choose the APFS or Mac OS Extended (Journaled) format and confirm the operation.

Step 4: Create the installer on the USB drive

Now, you’ll open the Finder application, go to the Applications folder and search for the installer you just downloaded. Right-click on “Install macOS 15 beta” and choose Show Package Contents. Then, go to the Contents folder and then to Resources.

In a terminal window, you’ll type sudo and drag the createinstallmedia file into the terminal. Then, you’ll type --volume followed by a space.

Drag the USB drive from Finder to the terminal window to complete the command, which should look similar to this:

sudo /Applications/Install macOS 15 beta.app/Contents/Resources/createinstallmedia --volume /Volumes/NAME_OF_YOUR_USB

When you’ve done this, press Enter (↵), enter the administrator password when prompted, confirm by pressing y, and press Enter (↵) again to start the process.

Once the terminal indicates that the process has finished, your USB drive with the macOS Sequoia installer will be ready.

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With this, you’ll be able to perform multiple installations without the need for repeated downloads, which is ideal for environments with limited internet connection, or simply to ensure a clean and efficient operating-system installation.