• How to Downgrade Big Sur to Catalina without Losing Data? To downgrade Big Sur to Catalina without losing data, here are 6 steps to follow. Before the downgrade, your data matters the most, so don’t forget to back them up though it takes time to finish a backup. Prepare your Mac for downgrade. You should quit running programs.
• When your Mac starts reinstalling MacOS Catalina, it’s going to take an hour or two to finish, so stay patient. The good news is that your files and apps — unless corrupted — should be saved.
• In this video we will go over how to Install macOS Catalina 10.15 without losing your data. It is a new feature in the new released macOS Catalina will save.

I recently upgraded to Catalina (everything is running fine, no issues with the OS), but decided to do a clean wipe of the drive to start fresh. Normally, I'd just boot into recovery mode, erase 'Macintosh HD', then reinstall the OS. But with the upgrade to Catalina, I now have 'Macintosh HD' and 'Macintosh HD - Data'. The most likely one might just be download Catalina from the app store and just do install Catalina on Big Sur's partition. If it doesn't from within Big Sur, you could make an USB installer, and try to install Catalina on Big Sur's partition from system recovery (yes, you do not need to format the drive to install over a partition that has data).

Are you trying to revert or downgrade your new macOS or Mac OS X to the previous version on the Mac computer? If yes, stay here. Just follow the provided guidance below to bring your previous macOS or Mac OS X back without losing any data:

Workable Solutions	Step-by-step Troubleshooting
Method 1. Use Time Machine	Start Mac and hold Command + R keys > Enter Recovery Mode > Insert Time Machine drive...Full steps
Method 2. Use USB Bootable Drive	Back up data first > Plug in USB and launch Disk Utility > Erase USB > Rename it as 'My Volume'...Full steps
Bonus Tip. Recover Data	After reverting macOS or Mac OS X, run EaseUS Mac file recovery software > Scan and recover lost data ...Full steps

Methods on this page can be applied to all Mac systems including the latest Big Sur, Catalina, Mojave, High Sierra, Sierra, and old Mac OS El Capitan, etc.

Tip: Backup Mac data before downgrading macOS or Mac OS X

It's highly recommended for you to back up all important Mac data first before you start downgrading Mac OS to an older system.

You can either choose third-party Mac backup software to back up Mac data to an external hard drive at once or choose Time Machine to back up all wanted data with ease.

Considering data security, it's also highly recommended for you to backup all important data into an external hard drive.

If you prefer to use Time Machine, here are the details:

• Click 'Finder' > 'Preference'> Check 'Hard disks box' underShow these items on the desktop.
• Open the backup disk and create a file folder and name it, for example, 'My Backup'.
• Open the Mac disk and click'Users' file folder > Select all files and data that you want to back up and drag to the My Backup file folder.

Wait for the process to finish. After backing up all data, then you can start to revert macOS with ease. Here, you'll find two methods for you to downgrade macOS without losing data and you can choose either one as a guide.

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

So if you have created backups for your Mac data and macOS, follow the below steps for a guide. If you haven't created such a backup, please jump to Method 2 to downgrade Mac OS.

1. 1. Start or restart your Mac and hold command+ R keys to enter theRecovery Mode, or hold the Option/Alt and then choose the Recovery option.
2. 2. Insert the hard drive used for Time Machine and chooseto Restore from Time Machine Backup under OS X Utility, choose the inserted hard drive.

1. 3. Choose the most recent data and time when the Mac was still running the current macOS.
2. 4. Select the main disk drive where the backup was stored and it is usually named Macintosh HD. Click Restore.

Then all you need is to wait for the computer to restore and gain Yosemite again. It will usually take a few hours or all day long, depending on how much data need to be restored.

Method 2. Create USB Boot Drive and Revert Back to Old macOS or Mac OS X

This method is set for users who have no Time Machine backups. And if you have no backups of your current macOS or Mac OS, use Time Machine to back up your important data first and the system first.

Then follow the below steps to downgrade Mac OS now: (The ways to download new macOS and old Mac OS X are different. Make sure that you've followed the right guide for downgrading the Mac system.)

Downgrade macOS (e.g: Downgrade macOS Mojave to High Sierra)

1. 1. Plug an external USB drive (with 16GB min), launch Disk Utility, and select the USB drive, click Erase.
2. 2. Rename the USB drive as 'MyVolume' and choose APFS or Mac OS Extended as the format, click Erase. Quit Disk Utility when the process is done.

3. To to Finder and launch Terminal, type: -sudo /Applications/Install macOS High Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume --applicationpath /Applications/Install macOS High Sierra.app and hit Return.

1. 4. Enter your Admin Password as required, wait until the process is done.
2. 5. Restart the Mac, hold the Option key.
3. 6. When the option to select a boot disk appears, choose the installer disk (the external USB drive) you created.
4. 7. High Sierra will start the installing process. When it's finished, restart your Mac and the Startup Assistant will appear. Then go through the steps to set up your Mac.

If your Mac is shipped with Mojave, you can directly downgrade Catalina to Mojave with the below tips:

1. 1. Restart Mac, hold Command + Option + Shift + R keys to boot into Recovery Mode. You can also press Command + R to enter the Recovery Mode.
2. 2. Click on 'Disk Utility', select the disk with Mojave installed, and click 'Erase'.

1. 3. Rename the disk, select Mac OS Extended or APFS as the file format, click 'Erase'. Quick Disk Utility by then.
2. 4. Re-enter the Recovery Mode, and select 'Reinstall macOS' and press 'Continue'.

By doing so, the old High Sierra will be installed on your Mac automatically.

Downgrade Mac OS X (e.g: Downgrade Mac OS X Yosemite to El Capitan)

1. 1. Download the OS X Yosemite installer from Mac App Store.
2. 2. Download the Diskmaker X app to create a bootable USB drive for El Capitan's downgrade.
3. 3. Insert a USB drive into Mac, launch Diskmaker X, and choose OS X Yosemite 10.10. Then the Diskmaker X will do the rest jobs for you.
4. 4. Keep the USB drive inserted into the PC, restart Mac. Hole Option/Alt and chose USB drive in the menu while rebooting Mac.
5. 5. Go to Utilities and select Disk Utility at the Install OS X menu.
6. 6. Select Macintosh HD and choose Erase. Be sure that selected under the Format field is Mac OS Extended (Journaled).
7. 7. Return to Install OS X menu and select Continue to begin the installation of OS X Yosemite.
8. 8. After all these, all you need is to be patient in installing Yosemite on your Mac.

Bonus Tip: Restore Lost Data after Downgrading macOS/Mac OS X(without backups)

This method is for users who have forgotten to back up important data before downgrading Mac OS. And if you lost data after Mac OS reinstallation or downgrading, here is the solution - to restore lost data after Mac OS X downgrading or reinstallation with powerful Mac data recovery software.

EaseUS Mac data recovery software supports to restore whatever you lost in Mac and it's fully compatible with all Mac OS above 10.8

And if you happen to lost important data after Mac OS downgrading, let EaseUS Data Recovery Wizard for Mac help you out. Three steps will do all jobs.

Step 1. Select the disk location (it can be an internal HDD/SSD or a removable storage device) where you lost data and files. Click the 'Scan' button.

Step 2. EaseUS Data Recovery Wizard for Mac will immediately scan your selected disk volume and display the scanning results on the left pane.

Step 3. In the scan results, select the file(s) and click the 'Recover Now' button to have them back.

A new macOS update will require that you reinstall macOS and sometimes you may lose data in the process. So, how can I reinstall macOS without erasing data? This is the focus of this article. However, before going into the details, you must understand that there are other reasons why you may need to reinstall macOS other than the release of a new update. Some of the other reasons why you may require macOS reinstallation include a system crash or slow performance of your Mac. Whether you want to reinstall the latest Mojave or Catalina, the fear of losing data is real. However, you don’t have to worry about this. In this post, we will share steps that you can follow to install new macOS without losing data.

Prep Work: What to do before Reinstalling macOS

Before you reinstall macOS on your system, you must have everything in place. You must ensure that nothing will stop the reinstallation halfway as this can disrupt the optimal performance of your system. The tips highlighted below will help you prepare for a smooth reinstallation process.

• Make sure you have a minimum of 8.8GB storage space and 2GB memory on your system.
• Ensure that your computer’s battery life is at a minimum of 45% before you launch the installation process.
• Make sure that your Mac is connected to a reliable WiFi connection.
• Check to see that your Mac Apps have been updated to the latest versions.
• Ensure that your data are backed up and you can also generate backups for your current Mac data on Time Machine.

It is recommended that you back up your data on an external hard drive to avoid unexpected problems or system update failure. When you are sure that your data has been backed up, you can start the reinstallation process. When you want to reinstall macOS without losing files, the best option is to go through macOS recovery mode. This will make it possible to reinstall the macOS, erase or repair disks, restore files from Time Machine, and much more.

How to reinstall macOS

You can easily reinstall macOS without losing any data irrespective of the reason why you want to launch the process in the first place. The steps below will guide you through the process in detail.

Step 1: Launch your Mac using the macOS Recovery mode. To do this, turn on your system and simultaneously press and hold the ‘Command + R’, ‘Option + Command + R’, or Shift + Option + Command + R. When the Apple logo or a spinning globe or a popup for the firmware password comes up, release the keys.

Step 2: A list of Utilities Window will come up and you have to select the ‘Reinstall macOS’ option and then click on the ‘Continue’ button.

Step 3: Follow the prompting on the screen to select the specific hard drive that you want to install the Operating System. The next step is to launch the installation process.

Step 4: Do not close the lid of the Mac or put it to sleep while the installation is ongoing. You may notice that your Mac is restarting over and over again. Do not worry about this because it is normal. You may also see the screen go while during the installation. Do not panic. All you have to do is to wait for the completion of the process.

When the process is finished, your Mac system will restart, and that completes the installation process. If you lose data while reinstalling macOS, you can easily restore the lost file using professional data recovery software.

How to Recover Lost Data after Reinstallation of macOS

If you notice that you have lost data while reinstalling macOS, it is recommended that you recover the data as soon as you can. We recommend that you use iBeesoft Data Recovery for Mac because it is the best software you can trust to recover all lost files seamlessly.

The iBeesoft Data Recovery for Mac is a professional data recovery software that enables you to recover lost/deleted files from your system’s hard disk and other storage devices. Irrespective of the size or nature of the data loss, you can trust it to recover all lost or deleted files from Mac desktops and other storage devices. It works 100% to quickly recover and restore data, including documents, photos, music, videos, and other files.

Your Effective Data Recovery Software for macOS

• Recovers permanently deleted folders and files from emptied trash.
• Recover and restores data from formatted hard drive, USB drive, SD cards, and other external storage devices.
• Completely compatible with APFS drive in the latest macOS.
• Retrieves lost data on Mac caused by deleted, inaccessible, hidden, damaged, repartitioned disk, or volume loss.

How Do I Reinstall Macos Without Losing Data

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Guide to Recover Lost Data Caused by macOS Reinstallation

Reinstall Catalina Without Losing Files

The first step is to download and install the Apple data recovery software on your system. You don’t have to worry because it is virus-free and compatible with the latest Mac OS. After the installation, you can follow the steps below to restore lost data after Reinstallation of macOS.

Step 1: Select the file types that you want to recover on Mac. When you launch the software, the main window will popup and you will see the file types. All files are checked by default, so you have to uncheck the files that you don’t need. When you are done, click ‘Start’ to begin the recovery process.

Step 2: Another window will pop up and you will see the volume of the Mac and the external hard drives that are available for a scan. Select the appropriate drive where you want to recover data from and click the ‘Scan’ button to start the scan process.

Step 3: Preview and recover deleted files on Mac system. Depending on the size of the data you want to recover, it may take from seconds to a few minutes to scan the files. When the scan process has been completed, all the found files will be displayed in the result window. Preview the files accordingly and select the ones you need and click ‘Recover’ to save them on your Mac.

Reinstalling macOS without losing files is very easy. So, if you have been asking how to reinstall macOS without losing data, the steps highlighted above is the right way to do it. If you lose data in the reinstallation process, you can easily recover them using iBeesoft Data Recovery for Mac.