Tips & Advice
Danish Kapoor
Danish Kapoor

How to revert to old macOS version on Mac?

In some cases, you may want to downgrade to an older version of macOS installed on your Mac. Various reasons may underlie this need. For example, you may need an older version of macOS to open older files. Or, if you are a software developer, you may need to test your software with an old version. You should know that in such cases, it is possible to install macOS old version.

Apple updates macOS, its operating system specifically for Macs, every year. New versions of macOS are being released, bringing various improvements, new features and compatibility updates compared to the previous year. However, although updates often occur without problems, there are also users who need to revert to old macOS versions from time to time. Apple ends support for older macOS versions over time, and online updates may also disappear. However, Apple continues to make some older macOS versions available for installation through its support site. You can reinstall to an older macOS, as long as your hardware supports these versions.

macOS downgrade installation: Getting Started

The important thing is to back up all data on your Mac before starting the rollback. This is especially true for a backup of the Mac’s internal disk because we will be recreating the entire disk and deleting the contents. At this point everything on your internal drive will be deleted.

After you take the backup, note the key locations on your Startup Disk that contain files you’ll want to move after restoring:

  • Applications
  • Library
  • Logged in user folder (~)
  • System preferences
  • Application Support
  • Fonts
  • Hidden configuration files

Also note the Downloads and Documents folders inside the user folder. You will also need to backup the files here before reinstallation.

The user folder also contains Music and Movies folders. If you use Apple Music, by default your music collection is stored in the Music folder. Therefore, make a backup of this folder as well so that it is not deleted after the rollback.

The file structures inside both the /Library and ~/Library folders are quite similar, but since there are more items under the ~/Library folder, you will need to be more careful during the process.

There is also a /Library folder where the logs are stored. If you want to keep current log files on your Mac, back up this folder as well.

In both Library folders, you can check what has changed by sorting by date.

If you use Apple Photos (Photos), by default the Photos library is located at ~/Library/Photos/Syndication.photoslibrary.

The Preferences folder in both locations holds most of your applications’ preferences. Therefore, make sure to back up these as well.

Important: Don’t forget the guide

An important element that most users overlook during backup is Apple’s Contacts application. If you have a locally stored Contacts, don’t forget to export your address list to your backup drive. If you do not do this, all your Contacts will be lost.

You can perform this operation within the Contacts application using the File->Export->Contacts Archive… menu item.

If you set up iCloud for contacts, you’ll have fewer problems because your contacts will be stored online and can be retrieved later.

Once you have completed all the backups, you can move on to the next step: deleting the Internal Startup Disk.

Note that when you reformat your Internal Startup Disk, everything on your Mac’s Desktop will also be deleted.

macOS old version installation: Restarting in recovery mode

Apple’s Recovery Mode is a special application built into your Mac’s firmware. When you start in Recovery Mode, your Mac loads this application instead of loading macOS. Recovery mode has essential utilities that will allow you to reformat, test and reinstall MacOS from scratch. Prominent among these applications are; Disk Utility, Restore from Time Machine and macOS installer.

When you update your Mac’s firmware to the latest version from Apple, it also updates to the latest supported version of the macOS installer. Therefore, you may want to check Apple’s Support website first to see if there are any new firmware updates for your Mac model.

If your Mac’s firmware is up to date, you’re ready to boot into recovery mode.

To enter Recovery Mode on an Apple Silicon-based Mac, turn off your Mac, then press and hold the power button until the Options menu appears. When the menu appears, click on the Options icon. This allows booting into Recovery mode.

On an Intel-based Mac restart the system and hold down Command-R on your Mac’s keyboard. This will boot into Recovery Mode.

macOS old version installation: Run Disk Utility

After rebooting into Recovery Mode, open the program by clicking the Disk Utility icon on Apple Silicon-based Macs. On Intel-based Macs, Disk Utility is usually found in the menu bar at the top of the screen.

While in Disk Utility, you’ll want to select the internal drive from the drive list on the left and then click the Erase icon in the toolbar at the top of the window.

When you click the Delete button, you will be asked to choose a name and format for your new volume (partition). Enter a name and select APFS as the volume format.

Be sure about what you’re going to do, because as soon as you click the Delete button, everything on your Mac’s built-in disk will be gone forever. Disk Utility will erase your Mac’s internal drive with the name you specified and add a new APFS volume to it. This way you will have a clean Mac with nothing.

macOS old version installation: Run the macOS installer

Once your Mac is wiped, exit Disk Utility and return to the firmware’s main menu. From here you can select the macOS installer built into the firmware and reinstall macOS on the volume you just created on your internal drive.

This process may take some time. If you’re using a newer model Mac and it’s connected to the internet, the macOS installer can also download and install updates.

Be patient. Once the macOS installer is complete, your Mac will be directed to restart. On newer models, automatic reboot may occur.

Either way, when your Mac restarts, it will boot to the version of macOS you just installed. You can access Finder by following the macOS installation screens.

macOS old version installation: Restore important files

When you return to Finder, you need to copy any important files you backed up from your previous macOS installation to your new macOS installation.

To do this, you first need to show hidden files in Finder and then copy important files from your backup to your new Startup Disk.

If you have a full backup of your Mac’s drive, you can try using Apple’s Migration Assistant, located in the /Applications/Utilities folder.

Migration Assistant will automatically attempt to restore user and settings files from the backed up version to your new installation.

If you don’t want to use Migration Assistant, you’ll need to copy back important files from your backup. Most of these files are the files and folders mentioned above. They are usually located in two Library folders and the user folder.

Don’t forget to also copy any important hidden files from your original user folder to your new user folder. It is not necessary to copy back all backed up system files, just those that are important for your specific settings and files.

Once the files are restored from your backup, you need to restart your Mac for the system to reload the restored settings.

Finally, run the System Preferences application in the /Applications folder and run General->Software Update again for the latest updates.

Note: If you have reverted back to an older version of macOS, it is important that you do not run the update. The update will upgrade to the latest full version of macOS that your Mac supports.

In this case, you can usually update the macOS version you reverted to to the last supported sub-version by manually downloading macOS updates for the older macOS version and running them from the Finder.

A note about macOS versions and firmware

One thing to know about macOS installers is that Apple’s latest installers do not allow you to install an older version of macOS over a new version. On some Macs, it also won’t let you restore an older version from Recovery Mode to a volume containing a newer version.

Therefore, it is best to erase the internal drive before restoring any version of macOS. Also note that it is usually not possible to downgrade your Mac’s firmware to an older version after a firmware update.

Therefore, it is important to think carefully before updating which version of macOS is stored in the firmware.

Alternative method: Downloadable installers

Another option is to obtain a downloadable version of an older macOS installer from the Mac App Store.

Apple offers several versions of older macOS installers in the App Store. If you use this method, keep in mind that older installers do not allow you to install an older version of macOS over a new version.

You can find older installers in the Mac App Store by searching for “macOS installer.” But the App Store is usually just

shows the two latest versions. For older versions, you’ll need to find specific links from the web and then navigate to them in the App Store.

You may want to use an older downloadable installer because your Mac’s firmware may be more current than what is needed to restore an older version of macOS, or you may not be able to use Recovery mode.

In these cases, you need to install the old macOS version on an external drive, boot from that drive, and then erase the internal drive and reinstall macOS from the external drive.

It is not possible to delete macOS from the drive you run it on. Therefore, to reinstall macOS you will always need another drive from which your Mac can boot.

If you think you may need to roll back to an older version of macOS in the future, it may be helpful to keep copies of old downloadable macOS installers.

In this article, we have examined in detail how you can roll back to an older version of macOS than the version installed on your Mac. This process can be accomplished using several different methods. Which method you choose will depend on your Mac model, macOS version, and personal preferences.

Before trying any method, make sure you have a full backup of your internal drive.

Danish Kapoor