Apple is set to release macOS Sonoma on September 26, and whenever a new operating system is released for the Mac, some users prefer to perform a clean installation. This article explains how to perform what is effectively a clean install of Sonoma using a built-in option that's available on Apple silicon-powered Macs and Intel Macs with a T2 security chip.

Apple WWDC23 macOS Sonoma hero

Clean installing macOS is often done to remove annoying quirks and strange behaviors that a Mac may have inherited over time, and can also help to reclaim disk space caused by junk files left by third-party apps. However, even if neither of these issues have arisen for you, sometimes it's just nice to start afresh for that "brand new Mac" feeling and then migrate your apps, documents, and data, either manually, or by migrating from a Time Machine backup.

Clean installing previous versions of macOS usually involves creating a bootable copy of the macOS installer on a flash drive or USB stick and then reformatting your drive before installing the bootable copy on your Mac, or using macOS Recovery to reinstall the Mac operating system over an internet connection. Since macOS Monterey, however, Apple has included a third option for newer Macs that offers a very simple and straightforward way to erase your Mac without needing to reinstall the operating system.

Following in the footsteps of the iPhone and iPad, Apple silicon Macs and Intel Macs with a T2 security chip (2017-2020 models) now have an "Erase All Content and Settings" option available in macOS Monterey and Sonoma. Because storage is always encrypted on Mac systems with Apple silicon or the T2 chip, the system is instantly and securely "erased" by destroying the encryption keys.

erase Mac
Not only does this effectively erase all user data and user-installed apps from your Mac without reinstalling macOS, it also signs out your Apple ID, removes your Touch ID fingerprints, purchases, and all Apple Wallet items, and turns off Find My and Activation Lock, making it far easier to restore your Mac to like-new factory settings.

This ability means you can simply download and install ‌macOS Sonoma‌ over your current macOS version when prompted, and then select the new erase function in Sonoma, which will erase your Mac and leave the core macOS system intact. After erasing the Mac, it will display the Setup Assistant and be ready to be set up like new. You can then migrate your data manually or by using the Setup Assistant's migration option. The following walkthrough breaks down the steps involved.

  1. Before you do anything else, back up your data using Time Machine or your preferred backup method.
  2. In macOS, click the Apple () symbol in the menu bar and select System Settings.
  3. Click General -> Software Update.
  4. Allow Software Update to ping Apple's servers, then click Upgrade Now to download the Sonoma installer when it appears. You can continue to use your Mac while the installer is being downloaded. Once the installer has downloaded, you'll receive a prompt. Click to install the new version of macOS and wait for the installation to complete.
    settings

  5. Once your Mac has restarted into Sonoma, click the Apple () symbol in the menu bar and select System Settings....
  6. Select General -> Transfer or Reset -> Erase All Content and Settings.
    settings

  7. Enter your admin password in the Erase Assistant dialog prompt and click OK.
  8. Note all the settings, data, media, and other items that will be removed. Click Continue if you're sure.
    erase Mac

  9. Click to sign out of your ‌Apple ID‌, then click Erase All Content & Settings in the prompt to confirm.
    erase mac

  10. Allow the erase process to complete. Your Mac may restart more than once during the process, after which you may be prompted to activate your Mac over Wi-Fi.
  11. Once finished, you'll see the "hello" message on your Mac's screen, indicating the Setup Assistant is ready. Follow the onscreen instructions, and if desired, elect to migrate your data from a Time Machine backup when the option appears.
    hello Mac

That's all there is to it. Even if you're not clean installing ‌macOS Sonoma‌ today, the new option makes it far more convenient to restore your Mac to factory settings, whether you simply want to start afresh with your Mac in future or plan to sell or gift it to another person.

Related Roundup: macOS Sonoma
Related Forum: macOS Sonoma

Popular Stories

apple tv 4k yellow bg feature

When to Expect a New Apple TV to Launch

Tuesday April 9, 2024 8:30 am PDT by
It has been nearly a year and a half since the current Apple TV was released, so the device is becoming due for a hardware upgrade. Below, we recap rumors about the next Apple TV, including potential features and launch timing. The current model is the third-generation Apple TV 4K, announced in October 2022. Key new features compared to the previous model from 2021 include a faster A15...
iPhone 16 Camera Lozenge 2 Colors

iPhone 16 Plus Rumored to Come in These 7 Colors

Wednesday April 10, 2024 3:52 am PDT by
Apple's iPhone 16 Plus may come in seven colors that either build upon the existing five colors in the standard iPhone 15 lineup or recast them in a new finish, based on a new rumor out of China. According to the Weibo-based leaker Fixed focus digital, Apple's upcoming larger 6.7-inch iPhone 16 Plus model will come in the following colors, compared to the colors currently available for the...
iPhone 16 Pro Sizes Feature

Alleged iPhone 16 Battery Details Show Smaller Capacity for One Model

Tuesday April 9, 2024 3:46 am PDT by
Apple's upcoming iPhone 16 lineup will feature bigger battery capacities compared to previous-generation models with the exception of the iPhone 16 Plus, which will have a smaller battery than its predecessor. That's according to the Chinese Weibo-based leaker OvO Baby Sauce OvO, a relatively new source of supply chain leaks with an as-yet unproven track record for accuracy. The iPhone 16 ...
apple silicon feature joeblue

Macs to Get AI-Focused M4 Chips Starting in Late 2024

Thursday April 11, 2024 10:10 am PDT by
Apple will begin updating its Mac lineup with M4 chips in late 2024, according to Bloomberg's Mark Gurman. The M4 chip will be focused on improving performance for artificial intelligence capabilities. Last year, Apple introduced the M3, M3 Pro, and M3 Max chips all at once in October, so it's possible we could see the M4 lineup come during the same time frame. Gurman says that the entire...
M3 iPad Feature 3

Apple Event for New iPads Still Considered 'Unlikely' Following Delays

Tuesday April 9, 2024 6:37 am PDT by
Apple is "unlikely" to hold an event to announce new iPad Pro and iPad Air models, according to sources cited by Taiwanese supply chain publication DigiTimes. Bloomberg's Mark Gurman already said Apple was not planning to hold an event for the new iPads, but he made this claim back in early March, before it was reported that the devices were postponed due to manufacturing delays. With the...
iOS 18 WWDC 24 Feature 2

iOS 18 May Feature All-New 'Safari Browsing Assistant'

Wednesday April 10, 2024 6:11 am PDT by
iOS 18 will apparently feature a new Safari browsing assistant, according to backend code on Apple's servers discovered by Nicolás Álvarez. MacRumors contributor Aaron Perris confirmed that the code exists, but not many details are known at this time. Álvarez said it seems like the browsing assistant will use iCloud Private Relay's infrastructure to send relevant data to Apple in a...