how to downgrade macos big sur
how to downgrade macos big sur

how to downgrade macos big sur

If you’ve recently upgraded to macOS Big Sur and are experiencing difficulties, you’re not alone. Many users have reported encountering various issues ranging from compatibility problems to performance glitches after installing the new operating system. If you’re facing similar challenges or simply prefer the stability of an older macOS version, downgrading your system to a previous iteration may be the solution you seek. This article will guide you through the comprehensive process of reverting to an older macOS version, providing clear and detailed instructions for a smooth and successful downgrade.

Understanding the Prerequisites

Before embarking on the downgrade process, it’s crucial to understand some essential prerequisites:

  1. Time Machine Backup: Before you proceed, ensure you have a recent Time Machine backup of your Mac. This backup will serve as a safety net in case anything goes wrong during the downgrade.
  2. Compatibility Considerations: Keep in mind that downgrading to an older macOS version may not be compatible with certain applications or hardware devices. Check compatibility before downgrading to avoid potential issues.
  3. Time Requirement: The downgrade process can take several hours, depending on the speed of your Mac and the size of your backup. Plan accordingly and set aside ample time for the procedure.

Section 1: Preparation Phase

Backing Up Your Data

  1. Connect an external storage device (such as a USB drive or Thunderbolt hard drive) to your Mac.
  2. Launch Time Machine by clicking on the Apple menu and selecting Time Machine.
  3. Click "Select Backup Disk," choose the external storage device, and click "Use Disk."
  4. Start the backup process by clicking "Back Up Automatically."

Creating a Bootable Installer

  1. Download the desired macOS installer from Apple’s website onto a USB flash drive.
  2. Format the USB flash drive using Disk Utility as "MacOS Extended (Journaled)."
  3. Open Terminal and enter the following command, replacing "MyVolume" with the name of the USB flash drive:
sudo /Applications/Install macOS Big --volume /Volumes/MyVolume

Section 2: Downgrade Procedure

Restarting in Recovery Mode

  1. Shut down your Mac and wait a few seconds.
  2. Press the power button and immediately hold down the Command(⌘) and R keys.
  3. Release the keys when you see the Apple logo or a spinning globe.

Erasing the macOS Installation

  1. In Recovery Mode, select "Disk Utility" from the Utilities menu.
  2. Select the internal storage device (usually named "Macintosh HD") from the left sidebar.
  3. Click the "Erase" tab and choose "Mac OS Extended (Journaled)" as the format.
  4. Click "Erase" to wipe the internal storage device.

Reinstalling the Older macOS

  1. Quit Disk Utility and return to the Recovery Mode menu.
  2. Select "Reinstall macOS Big Sur" (or the desired older version) from the options.
  3. Click "Continue" and follow the on-screen instructions to complete the reinstallation.

Section 3: Post-Downgrade Recovery

Restoring from Time Machine Backup

  1. Once the reinstallation is complete, connect the external storage device containing the Time Machine backup.
  2. Open Time Machine by clicking on the Apple menu and selecting Time Machine.
  3. Select "Restore from Time Machine Backup," choose the external storage device, and click "Continue."
  4. Select the backup you want to restore from and click "Restore."

Applying System Updates

After restoring from the backup, it’s recommended to apply any available system updates. This will ensure that your Mac has the latest security patches and bug fixes.

| Action | macOS Version | Time Required |
| Create Bootable Installer | Varies | 1-2 hours |
| Restart in Recovery Mode | N/A | Less than 5 minutes |
| Erase macOS Installation | Varies | 30-60 minutes |
| Reinstall Older macOS | Varies | 1-2 hours |
| Restore from Time Machine Backup | Varies | Dependent on backup size |
| Apply System Updates | Varies | 5-15 minutes per update |


Downgrading macOS Big Sur to an older version can be a straightforward process if you follow the steps outlined in this article. By understanding the prerequisites, preparing your system, and carefully executing the downgrade procedure, you can revert to a more stable and compatible macOS iteration. Remember to back up your data, create a bootable installer, and apply all necessary system updates after the downgrade to ensure a smooth and successful transition.

FAQ about Downgrading macOS Big Sur

1. Can I downgrade my Mac from Big Sur to an earlier macOS version?

Yes, you can downgrade to Catalina, Mojave, or High Sierra.

2. What do I need to downgrade?

  • A bootable USB drive with the desired earlier macOS version.
  • A compatible Mac that can run the earlier macOS version.

3. How do I create a bootable USB drive?

  • Download the macOS installer for the desired version from the Apple website.
  • Use Disk Utility or a third-party tool like Etcher to create a bootable USB drive.

4. How do I boot from the USB drive?

  • Turn off your Mac and hold down the Option (Alt) key.
  • Turn on your Mac and wait for the boot menu to appear.
  • Select the USB drive from the menu and press Enter.

5. What happens when I downgrade?

  • Your Mac will be wiped clean and the earlier macOS version will be installed.
  • All your data, files, and apps will be lost.

6. Can I recover my data after downgrading?

No, downgrading wipes your Mac clean. You cannot recover data from the previous macOS version.

7. Will my apps work on the earlier macOS version?

It depends on the apps. Some apps may require newer versions of macOS, so they may not work or may have reduced functionality.

8. Is there a faster way to downgrade?

No, downgrading requires a complete erase and reinstall of the earlier macOS version.

9. What should I do before downgrading?

  • Back up your Mac using Time Machine or another method.
  • Uninstall any apps or drivers that may not be compatible with the earlier macOS version.

10. I downgraded and now my Mac won’t start up. What should I do?

  • Try re-installing the earlier macOS version from the Recovery Mode.
  • Contact Apple Support for assistance.