macOS Sequoia downgrade guide: Easily return to the Sonoma system

Difficulty: 5/10

Required Equipment: Hard drive for backup (usually at least 500GB). If you choose to downgrade using the bootable macOS installer, you need a flash drive (32GB).

Time: up to 3 hours

Tools: Time Machine. Optional: Get Backup Pro, CleanMyMac.

Every fall, my colleagues from IT security will give the same advice: “After a new operating system is released, wait a few days before upgrading. Early versions often have bugs or compatibility issues that can disrupt your work.”

I usually do this, but this year my curiosity beats everything. Not only did I skip the waiting period, I also installed the Sequoia beta. Sure enough, after a few days of testing, I had to downgrade.

If you upgraded too, and now want to roll back due to errors or other issues, you can also downgrade from macOS Sequoia to Sonoma. This guide shares my experience and tips – I hope you find it useful!

Before downgrading macOS Sequoia

The most important thing to do before you start downgrading is backing up and cleaning up your Mac.

Step 1. Prepare a backup

When you downgrade, you need to wipe the hard drive of your MacBook completely. This means a complete backup of your system (or at least the files that matter most to you).

To create a backup, you need a storage device. Ideally, it should be twice the size of a Mac hard drive.

Here is how to prepare a backup drive:

1. Connect the drive to your Mac.
2. Open Disk Utility and select Erashes.
3. In the Format drop-down menu, select APFS or Mac OS extension (logged), and then click Eraser.
4. Close Disk Utility.

Next, use Time Machine to create a backup:

1. Open Time Machine by going to System Settings > General > Time Machine.
2. Click Add Backup Disk, select the desired disk, and then click Set Disk.
3. If needed, set a password (you will need it later to restore the backup) and click Finish.
4. Click Options to configure the files you want to back up and the backup frequency, and then click Finish.

The backup should start automatically. If not, click the clock icon in the menu bar and select Backup Now. Wait for the backup to complete.

Step 2. Clean up the junk files of your Mac

I like to think of this step as cleaning up the construction site before starting a new build.

Over time, your Mac accumulates system junk files that may interfere with the smooth operation of the new operating system. Since it's nearly impossible to manually delete these junk files, I recommend using CleanMyMac. It is a Mac care app that removes system junk, removes viruses and speeds up the system.

To clean up your Mac:

1. Install and open CleanMyMac.
2. Click Scan.
3. View the junk file found and click Run to delete it.

This process takes up to 10 minutes and can free up several GB of space. Please check my results:

How to downgrade macOS Sequoia

There are three ways to restore macOS Sequoia updates: use Time Machine, Internet Recovery, or start the macOS USB installer. Which method to choose?

Downgrade with Time Machine

If you backed up your Mac before upgrading to Sequoia, the downgrade should be fast. You can restore your Mac to its exact state before the upgrade.

Note: If you create any important files or projects while using Sequoia, make sure you back up them as well before downgrading.

In my case, I only have some GB of files and programs, so I only backed up these. I found Time Machine inconvenient for selective backups, so I used GetBackup Pro. It's simple: you just select the file you want and the application will create a backup. In my experience, it also saves more space than the backup of Time Machine.

Here is how to downgrade from Sequoia using Time Machine:

1. Connect the drive with Time Machine backup to your Mac.
2. Restart your Mac in recovery mode.
   
   • For Intel-based Macs: Hold down Command R until you see the Apple logo.
     
   • For Apple Chip Mac: Press and hold the power button until you see the boot option.
3. Click Options > Continue > Recover from Time Machine > Continue.
4. Select the Time Machine drive and in the backup list, select the backup you created before upgrading to Sequoia.
5. Click Recover.

Follow the on-screen instructions and wait for the system to recover.

Use the Internet to restore downgrade

Internet Recovery will restore your Mac to the operating system it originally came with, not your previous one. Why the "Internet"? Because in this approach, your Mac downloads the operating system from Apple's servers. After that, you can upgrade to your favorite operating system.

As a reminder: You need to erase the entire Mac, so make sure you have a backup of your important files or a whole system.

Here is how to reinstall older versions of macOS using Internet Recovery:

1. Turn off your Mac.
2. Enter recovery mode. First, turn off your Mac. Then:

• For Intel Mac: Press and hold Shift Option Command R and press the Power button.
• For Apple chip Mac: Press and hold the power button until the Options button appears.

3. Select Disk Utility.
4. In the left pane, click your drive (usually called Macintosh HD).

Note: Make sure to select the entire disk, not just the volume. If you are not sure, click the View button on the left side of the Disk Utility and make sure Show All Devices is selected.

5. Press "Erase" and confirm your action. Wait for the erase process to be completed.
6. Connect to Wi-Fi.
7. Click Exit Recovery.
8. Click Reinstall macOS [Name] > Continue. Then, follow the on-screen instructions: Agree with the license terms, select the disk (usually Macintosh HD) to install the operating system, and wait for the installation to complete.

Downgrade using bootable macOS USB installer

For this method you need:

• A flash drive that turns it into a bootable installer. I was using a 16GB drive initially, but when I tried to burn Sonoma to it, I was missing…83MB. So I switched to 32GB USB.
• macOS Sonoma: Download it from the Apple Store. Downloading may take 1 hour or more depending on your internet speed.

Now, let's continue with the macOS Sequoia downgrade guide using the USB installer.

Step 1: Format USB

1. Plug the USB drive into your Mac.
2. Open Disk Utility, select your USB and click Erashes.
3. In the Format drop-down menu, select Mac OS extension (log-style), and then click Eraser.

Common Errors

If you don't see Mac OS extensions (logs) in the Format drop-down menu, it may be because you're trying to format the volume instead of the physical disk. To resolve this issue, go to the upper left corner, click View > Show All Devices, and select the physical disk in the left pane.

Step 2: Make USB bootable

1. Open the terminal and type sudo /Applications/Install\ macOS\ Sonoma.app/Contents/Resources/createinstallmedia --volume /Volumes/[您的USB名稱] (please replace [您的USB名稱] with the actual name of your USB drive).
2. Open Finder > Go to > Go to Folder, type /Volumes , and press Return.
3. Select your USB drive and drag it into the terminal.
4. Press Return, enter your password, and wait for the process to complete – this may take 30 minutes.

You should get the following results:

Step 3: Downgrade to macOS Sonoma

1. Turn off your Mac.
2. Press and hold the power button until the Startup option appears.
3. Select Install macOS Sonoma > Continue.
4. Select Disk Utility > Continue.
5. Select your hard drive (usually called Macintosh HD) and click "Erase" in the upper right corner.

6. In the Format drop-down menu, select APFS, and then click Erashes.
7. Wait for the process to complete, and then close the Disk Utility window.
8. Select Install macOS Sonoma > Continue.
9. Agree to the license agreement and follow the on-screen instructions.

The operating system installation will begin and will take about 30 minutes.

Prepare correctly to restore macOS Sequoia updates

The rules for downgrading from macOS Sequoia to Sonoma can be summarized as follows:

1. Make a backup. Back up any important files that you create on your current system or when using macOS Sequoia. If you plan to use Time Machine recovery, use this tool. Personally, I prefer Get Backup Pro because it is convenient and backups are more compressed.
2. Clean up your Mac. Don't bring unnecessary junk files to the new system. Use CleanMyMac to clean up system junk files.
3. Set aside time for this. This process can take 3 hours or more, so be prepared to avoid using your Mac during this period.

The apps I mentioned that help you prepare your backup are available on Setapp, a platform with over 250 macOS and iOS applications. You can try out all the features of all apps for free for 7 days.

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