Downgrading an operating system is the process of switching from a current version to an older one. As its name suggests, it's pretty much the opposite of updating your machine to a newer software release. You can downgrade the OS on most modern computers and smartphones, and this includes the latest Mac. So, for example, if you're running macOS Sonoma on your machine, you can downgrade macOS to a previous version. The process, however, isn't as simple as updating, so we'll be detailing it in the steps below.

Why you may want to downgrade macOS

Users may choose to downgrade macOS on their Apple computers for many reasons. Some popular causes include unsupported apps, broken system functionalities, battery drain, and more. By downgrading macOS to a previous, more stable release, a user may be able to fix what the new version has broken.

Another popular reason for downgrading macOS is switching from the beta to the stable channel. While you could switch off beta updates and wait for the next stable release instead of downgrading, sometimes a beta makes Macs unusable. In this case, your only option would be downgrading from the beta to the latest stable version.

Things you should know before downgrading macOS

As you may expect, downgrading macOS typically deletes all your locally stored files and restores the default system settings. So, when the process concludes, you'll have to set up your computer from scratch. That's why we advise uploading important files to a cloud storage service or moving them to an external hard drive.

Alternatively, you could back up your files using the built-in Time Machine app, but these backups typically include system files, too. Restoring the backup on an older version, by default, could also include system files from the newer operating system, and things could break. Time Machine backups were designed for those sticking to the same version or updating to a newer one, rather than downgrading. So, attempting to restore a new backup on an older OS is neither reliable nor a straightforward process.

The fast way to downgrade from macOS beta to a stable release

If you're on the beta channel and simply want to switch back to the latest stable release, then the process is relatively simple. It's also seemingly the only method that won't wipe your locally stored data. Nonetheless, we advise you to back up your important files anyway because system-level changes, such as downgrading, could always go wrong and cause unexpected data loss. To reinstall the latest stable macOS version, head to our dedicated guide and follow the steps listed there.

How to downgrade macOS using a bootable installer

If you want to downgrade to an older macOS version that isn't available through the previous method, then you will have to rely on a bootable installer.

1. Create a bootable macOS USB installer of the older macOS version you want to downgrade to.
2. Plug the USB flash drive into the powered-off, internet-connected Mac you want to downgrade.
3. Turn on the Mac, and continue to hold the Power button until you see the Startup window. This should display your bootable volumes, which include the flash drive you've plugged in.
4. Select the volume that packs the bootable installer.
5. This should open the macOS Installer, which provides you with the detailed instructions you must follow.
6. That's it! Once you go through the setup screens, you can start using your Mac again, and it'll be running the older macOS version.

How to downgrade macOS using a Time Machine backup

If you have created a Time Machine backup before updating to the newer macOS version, you can restore the older OS and your personal data through this method. But this method won't work if the only Time Machine backup(s) you have was created on the newer OS version you're trying to downgrade.

1. Connect the disk with the Time Machine backup(s) to your powered-off Mac.
2. Turn on your Mac, and continue to hold the Power button until you see the Startup window.
3. You should see Restore From Time Machine Backup, among other options. Click it.
4. Hit Continue.
5. A Restore from Time Machine screen will appear. Hit Continue again.
6. When prompted to pick the Restore Source, choose the disk that has the Time Machine backup(s).
7. This should show you a list of all the backups you've made through Time Machine, along with their OS version. Choose the latest backup you created before you updated to the newer version. So, the backup's OS version should be the old OS you're downgrading to.
8. This should trigger the downgrading process, and your Mac should be running the older OS when it concludes.

Downgrading macOS is doable yet inconvenient

As our guide shows, there are multiple ways to downgrade macOS. However, pretty much all of them are somewhat complex and not as convenient as updating the OS. In most cases, you will also be losing your data. That's why if you just want to switch from macOS beta to the stable version, we advise you to simply wait for the next stable release if using the beta for a few more days or weeks is bearable. Otherwise, if, for whatever reason, you want to use an older macOS version, you can pick the method that best matches your needs.