How to Clean Install macOS Sonoma? On September 26, Apple will release macOS Sonoma, and every time a new operating system for the Mac is released, some users prefer to make a clean installation. This article describes how to execute a clean install of Sonoma using a built-in option accessible on Apple silicon-powered Macs and Intel Macs equipped with a T2 security chip.
Clean installation of macOS is frequently performed to remove unwanted idiosyncrasies and weird behaviours that a Mac may have inherited through time, and it can also assist in reclaiming disc space caused by garbage files left by third-party software. Even if neither of these difficulties has occurred for you, it’s occasionally good to start over for that “brand new Mac” sensation and then migrate your programs, documents, and data, either manually or by migrating from a Time Machine backup.
Clean installation of previous versions of macOS typically entails creating a bootable copy of the macOS installer on a flash drive or USB stick and then reformatting your drive before setting up the bootable copy on your Mac or using macOS Recovery to reinstall the OS for your Mac over an internet connection. However, since macOS Monterey, Apple has added a third option for newer Macs that provides a very simple and straightforward way to delete your Mac without having to reinstall the operating system.
Apple silicon Macs and Intel Macs with a T2 security chip (2017-2020 models) now have an “Erase All Content and Settings” option in macOS Monterey and Sonoma, following in the footsteps of the iPhone and iPad. Because storage on Mac systems with Apple silicon or the T2 chip is constantly encrypted, the system is promptly and securely “erased” by removing the encryption keys.
This not only effectively erases all user data and user-installed apps from your Mac without reinstalling macOS, but it also signs out your Apple ID, removes your Touch ID fingerprints, purchases, and all Apple Wallet items, and disables Find My and Activation Lock, making it far easier to restore your Mac to like-new factory settings.
This means you can simply download and install macOS Sonoma over your current macOS version when prompted, and then use Sonoma’s new erase function to erase your Mac while keeping the core macOS system intact. After deleting the Mac, it will display the Setup Assistant and be ready to be configured as if it were brand new. You can then migrate your data manually or utilise the migration option in the Setup Assistant. The steps are broken down in the following walkthrough.
How to Clean Install macOS Sonoma?
- Back up your data using Time Machine or your favourite backup technique before proceeding.
- In macOS, select System Settings by clicking the Apple icon in the menu bar.
- Select General -> Software Update from the menu.
- Enable Software Update to ping Apple’s servers, then click Upgrade Now when it appears to download the Sonoma installer. While the installer is downloading, you can continue to use your Mac. You’ll be prompted after the installer has finished downloading. Wait for the installation to finish before clicking to install the new version of macOS.
- After restarting your Mac into Sonoma, click the Apple icon in the menu bar and select System Settings….
- Choose General -> Transfer or Reset -> Erase All Content and Settings from the menu.
- In the Erase Assistant dialogue box, enter your admin password and click OK.
- Make a list of all the settings, data, media, and other stuff that will be deleted. If you’re certain, click Continue.
- Sign out of your Apple ID, then confirm by clicking Erase All Content & Settings in the popup.
- Allow the erase process to finish. During the process, your Mac may restart several times, and you may be required to activate your Mac over Wi-Fi.
- When you’re finished, your Mac will display the “hello” message, signalling that the Setup Assistant is ready. Follow the onscreen instructions, and when prompted, choose to migrate your data from a Time Machine backup.
That’s the end of it. Even if you aren’t installing macOS Sonoma from scratch today, the new option makes it significantly more straightforward to restore your Mac to factory settings in the future, whether you simply want to start over with your Mac or plan to sell or gift it to someone else.