Downgrade macOS/Mac OS X to 2024 Safely Without Losing Data (for Big Sur/Catalina)

Have you ever tried to downgrade your new macOS or Mac OS X to the previous version on your Mac computer? If yes, then stay here. Just follow the guide provided below to revert back to previous macOS or Mac OS X without losing any data:

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These methods work on all versions of the Mac, including the latest Big Sur, Catalina, Mojave, High Sierra, Sierra, and older versions of macOS El Capitan and below.

Tip: Back up your Mac data before downgrading macOS or Mac OS X

Before you begin downgrading macOS, it's highly recommended that you back up all your important Mac data.

You can choose a third-party Mac backup software to back up data to an external hard drive all at once, or choose Time Machine to back up all the data you need easily.

Back up your Mac OS X data before downgrading from EI Capitan to Yosemite

For reasons of data safety, it is also strongly recommended that you back up all important data to an external hard drive.

If you prefer using Time Machine, here's how:

Click “Finder” > “Preferences” > Check the box under “Show these items on the desktop” for “Hard disks.” Open the backup disk and create a folder, naming it something like “My Backup.” Open the Macintosh HD, click on the “Users” folder > Select all the files and data you wish to back up, then drag them into the “My Backup” folder.

Wait for the process to finish. Once your data is backed up, you can proceed with downgrading macOS with ease. Here, you will find two methods to downgrade macOS without losing data, either of which you can use as a guide.

Method 1: Downgrade macOS or Mac OS X with Time Machine

If you have a backup of your Mac's data and macOS, proceed with the following steps. If you don't have such a backup, skip to Method 2 to downgrade macOS.

1. Start up or restart your Mac while holding down command + R to enter Recovery Mode, or start by holding Option/Alt and choose the Recovery option. 2. Insert the hard drive you use with Time Machine, select Restore From Time Machine Backup in the OS X Utilities window, and choose the inserted drive.

4. Select the main disk drive for the backup, usually labeled “Macintosh HD.” Click “Restore.”

Your Mac will then proceed to restore itself and reinstall Yosemite. This can take several hours or all day, depending on how much data needs to be restored.

Method 2: Create a USB installer and revert to an older version of macOS or Mac OS X

This method is for users who do not have a Time Machine backup. If you do not currently have a backup of your macOS or Mac OS X, back up your important data and system using Time Machine first.

Then, follow these steps to downgrade macOS: (Note that the process for downloading a new macOS and an older version of Mac OS X is different, so make sure you've followed the correct guide to downgrade your macOS.)

Downgrade macOS (for example, from macOS Mojave to High Sierra)

1. Connect an external USB drive with at least 16GB of space, launch Disk Utility, and select the USB drive. Click the "Erase" button. 2. Rename the USB drive to "MyVolume," choose APFS or Mac OS Extended format, and then click "Erase." Quit Disk Utility when finished.

3. Open Finder, then open Terminal, and enter the following command: sudo /Applications/Install\ macOS\ High\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume --applicationpath /Applications/Install\ macOS\ High\ Sierra.app, then press Return.

4. Enter your administrator password (if prompted), and wait for the process to finish. 5. Restart your Mac while holding down the Option key. 6. When presented with the Startup Manager, select the installer disk you created (the external USB drive). 7. High Sierra will begin installing. Once it's done, restart your Mac, and you'll see the "Startup Assistant." Follow the steps to set up your Mac.

If your Mac came with Mojave pre-installed, you can downgrade from Catalina back to Mojave by following these steps:

1. Restart your Mac and hold down Command + Option + Shift + R to enter Recovery Mode. You can also press Command + R to enter Recovery Mode. 2. Click on "Disk Utility," select the disk that has Mojave installed, then click "Erase."

3. Rename the disk, choose "Mac OS Extended" or "APFS" as the format, then click "Erase." This quickly uses Disk Utility. 4. Re-enter Recovery Mode and select "Reinstall macOS," then click "Continue."

This will automatically download the older version of High Sierra to your Mac.

Downgrade Mac OS X (for example, from Yosemite to El Capitan)

1. Download the OS X Yosemite installer from the Mac App Store. 2. Download the Diskmaker X application to create a bootable USB drive for downgrading El Capitan. 3. Insert the USB drive into your Mac and launch Diskmaker X, then choose OS X Yosemite 10.10. Diskmaker X will take care of the rest. 4. Keep the USB drive connected to your PC, then restart your Mac. Hold down the Option/Alt key to select the USB drive from the boot menu while your Mac restarts. 5. In the "Install OS X" menu, go to Utilities and choose Disk Utility. 6. Select Macintosh HD, then click Erase. Make sure you choose Mac OS Extended (Journaled) under the Format field. 7. Go back to the Install OS X menu and click Continue to start the installation of OS X Yosemite. 8. After this, simply wait for Yosemite to install on your Mac.

Additional Tip: Recover Lost Data After Downgrading macOS/Mac OS X Without Backup

This method is for those who forgot to back up important data before downgrading the Mac OS. If you lost data after reinstalling or downgrading Mac OS, there is a solution – use a powerful Mac Data Recovery Software to recover lost data after downgrading or reinstalling Mac OS X.

This Mac data recovery software can help you recover any lost data from your Mac, and it is fully compatible with all versions of Mac OS above 10.8.

If you have lost important data after downgrading Mac OS, let the Mac Data Recovery Wizard tool help you. It does all the work in just 3 steps.

Step 1: Search for the Lost File

Select the disk location where your lost data and files were stored (it can be an internal HDD/SSD or an external hard drive). Click on the “Search for lost files” button.

Note: Before you proceed with data recovery, it's recommended that you click “Disk Backup” from the left sidebar and create a backup of your HDD/SSD to prevent further data loss. After the backup, the software can recover data from your disk image, and you can use the HDD or SSD again.

Step 2: Preview the scan results

The software immediately scans the disk volume you select and displays images, documents, audio, video, and email in the left pane.

Step 3: Select the files and recover them.

Click on the data to preview, and then hit the "Recover" button to get them back.