Reinstall Macos Catalina Without Losing Data

Posted on 18-09-2021 by admin

Choose Reinstall macOS and select the new drive name as your target. Once in Setup Assistant choose to migrate your data from your Time Machine back up (Time Machine isn't using APFS, yet, so this.
The correct way to reinstall macOS Catalina is to use your Mac’s Recovery Mode: Restart your Mac and then hold down ⌘ + R to activate Recovery Mode. In the first window, select Reinstall macOS Continue. Agree to the Terms & Conditions. Select the hard drive you’d like to reinstall mac OS Catalina to and click Install.
The steps are as follows: a) Go to Apple menu System Preferences Software Update. B) In the Software Update window, click the Upgrade Now button beside macOS Big Sur. Image: macOS Update from Catalina to Big Sur. C) Once the software is downloaded, macOS Big Sur installer opens automatically.

After months of waiting, macOS Big Sur was released in November 2020. No matter how great macOS Big Sur is, you can experience performance issues as you update your Mac. The good thing is you can downgrade to the previous macOS version.

There are two ways to revert from Big Sur to Catalina. The first one involves restoring a Time Machine backup. The second, which is a bit lengthy, explains how to downgrade to Catalina using a bootable installer. Whichever way you choose, we'll provide step-by-step instructions to help you downgrade.

Open this article on your phone to make sure you do everything step-by-step.

How to downgrade from macOS Big Sur using Time Machine

Reinstall macos catalina without losing data connection

If you’ve backed up your Mac with Time Machine before upgrading to Big Sur, downgrading to Catalina will be easy. Here’s how to downgrade from macOS Big Sur to Catalina using Time Machine.

1. Back up your data

First, back up everything. Your Mac probably contains your personal data and documents that you don’t want to lose. So, to keep those alive after the downgrade, you need to back up your data.

Follow these steps: Click the Options button, select Desktop & Documents Folders, and then click. All the data from your Mac Desktop and Documents folder will be copied to iCloud Drive as a cloud backup. Now, after creating a backup of Mac system data, you can upgrade or reinstall the Operating System without the fear of losing data. 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.

You can use Google Drive, iCloud Drive, or any other cloud you prefer. After the backup is done, you can move on to the next step.

Before you begin reverting your Mac to macOS Catalina, it’s worth trying fixing performance issues on macOS Big Sur. Maybe you won’t need to downgrade at all.

CleanMyMac X can help identify and solve performance problems on your Mac. It’s a dedicated Mac cleaner that clears old junk and runs optimization tasks. It’s notarized by Apple, which means it’s safe for your Mac. Get CleanMyMac X for free to run a quick performance scan.

2. Erase your Mac’s hard drive

The first step is plugging your Mac into power (the downgrade process may take a while, and you don’t want your Mac to power off unexpectedly).

You’ll need to erase your Mac’s drive. This will remove everything from your Mac, but you can restore your data later from a Time Machine backup.

Restart your Mac (Apple menu > Restart).
Hold Command-R when your Mac’s rebooting. The Utilities menu should appear.
Choose Disk Utility.
Click Continue and select Startup Disk (usually located at the top of the list ).
Press Erase.
Select the APFS file format.
Choose GUID Partition Map and confirm.

Wait for the process to complete. Only after every piece of data is removed, can you clean install macOS Catalina.

3. Use Time Machine to restore your backup

You can now restore all your files and data and bring your Mac back to the condition it was in before you installed macOS Big Sur.

Reinstall macos catalina without losing data center

If your Time Machine backup is stored on the external drive, plug it in your Mac.

So, to restore your Time Machine Catalina backup:

Restart your computer and hold Command-R when it reboots.
Select the Restore From Time Machine Backup option on the Utilities window.
Press Continue.
Choose your Time Machine backup disk.
Select the backup you want to restore from. Choose the most recent backup that occurred before you installed macOS Big Sur.
Then, select a destination disk, where the contents of your backup will be stored.
Click Restore and press Continue.

The process may take some time. Your Mac will restart running macOS Catalina.

How to downgrade from macOS Big Sur using a bootable installer

If you didn’t back up your Mac with the Time Machine, it’s too bad. But, you can still downgrade to the previous OS version. Just follow the instructions.

1. Back up your files and data

Backing up your data is important. It prevents you from losing all the files and data that have existed on your Mac's drive for a while. So, don’t forget to back up your Mac before you start downgrading to Catalina.

2. Create a bootable installer

A bootable installer will help you safely roll back to Catalina. Here’s how to create a bootable installer:

You can go to the App Store and search for Catalina, then download it. Quit the installer, if it tries to install the OS.
If your Mac already runs macOS Big Sur, download the macOS Catalina here.
Get an external hard drive that has at least 12 GB of available storage and plug it in your Mac.
Launch the Disk Utility app and erase your hard drive selecting Mac OS Extended format.

Now, it’s time to transfer your Catalina installer to your hard drive:

Open Terminal (Applications > Utilities).
Paste this command and press Enter:

sudo /Applications/Install macOS Catalina.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume

The downloaded file, which is your bootable Catalina installer, should be in your Applications folder. MyVolume is the name of the hard drive; if your hard drive or flash drive has a different name, replace MyVolume with the name of your hard drive.

If prompted, enter your administrator password and press Enter again. Terminal won’t show anything when you type your password.
Follow the instructions that appear in the Terminal.
When Terminal says “done”, your hard drive should have the same name as the installer you downloaded (for example, Install macOS Catalina).

Quit Terminal and eject the hard drive.

Install macOS Catalina

Now, you can roll back from macOS Big Sur using the bootable installer.

Plug your hard drive (which is now your bootable installer) into your Mac.
Open System Preferences > Startup Disk. Choose your bootable installer as a startup disk and press Restart.

Your Mac should start up to macOS Recovery.
Make sure your Mac has an internet connection to download firmware updates (you can use the Wi-Fi menu in the menu bar).
In the Utilities window, select Install macOS.
Click Continue and follow the on-screen instructions.

Your Mac will then start installing macOS Catalina and will restart when it’s done.

Mac runs slowly after the update?

If your Mac is slow after the update, but you don’t want to perform this lengthy process and revert to the previous OS, you could try a quick solution. CleanMyMac X has a helpful Maintenance feature that could fix all possible problems on your Mac.

Open CleanMyMac X.
Go to the Maintenance module.
Press View All 9 Tasks.
Check the boxes next to the maintenance tasks you want to run.
Press Run.

Wait till CleanMyMac X runs the set of fixes to speed up your Mac.

Reverting to the previous macOS may seem like a terrifying task. But if you open this article on your phone or another device and follow the instructions, it will be much easier and faster. Don’t forget to clear your Mac before the backup – you will save a lot of free space and remove old clutter that slows down your machine.

Summary: Whenever a new version of the Mac Operating System is launched, it brings with it enhanced user experience, additional/improved features, and much more. Thus, as soon as a new Operating System is launched, you may want to upgrade your Mac system.

You need to reinstall the Operating System when your Mac becomes slow, gets infected by a virus, or suffers any other OS-related issue. It is to be noted to reinstall macOS might result in data loss.

However, you won’t lose your data while upgrading the Mac Operating System. Still, you must take a backup of your data before performing such operations. So, let’s first discuss the ways to back up the Mac data, and then we’ll learn how to upgrade or reinstall macOS.

In case you have lost data on Mac OS due to reinstalling of macOS- simply use Stellar Data Recovery for Mac Software. Advanced software to recover data from all kinds of data loss from your macOS.

How to Back Up Data Before Upgrading or Reinstalling macOS?

Here are some ways to back up your data on Mac:

1: Use Time Machine

Time Machine is the Mac system’s built-in backup feature. To automatically back up your personal data, such as documents, music, photos, apps, and email by using this feature, you need an external storage device.

Follow the given step-by-step instructions to back up your Mac data with Time Machine:

Plug an external drive into your Mac, such as a USB or Thunderbolt drive, to be used as the backup device.
Open System Preferences from the dock and clicks Time Machine.
Click Select Backup Disk to choose the Mac disk which needs to be backed up. When you select the backup disk, a new window pops up, containing the list of all external hard drives connected to your Mac.

Choose the external drive you connected and click the Use Disk button to start the backup process.

[NOTE]: Selecting ‘Encrypt backups’ would make your backup password protected. It will prompt you to create a password for the backup. To restore data from encrypted backups, you must provide the backup password.

Once the backup process is complete, you’ll get a notification.

2: Copy the Data to an External Drive

You can also simply copy the data to an external hard drive. To do so,

Connect an external drive, such as a USB, Thunderbolt, or FireWire drive to your mac system.
Copy the files you want to backup and paste them to the external disk. You can also do this by dragging the files to an external drive.
Check if all the required files are copied to the external drive.

3: Using iCloud Service

You can also back up your data on iCloud. Follow these steps:

From the dock, open System Preferences and click

Click the Options button, select Desktop & Documents Folders, and then click

All the data from your Mac Desktop and Documents folder will be copied to iCloud Drive as a cloud backup.

Now, after creating a backup of Mac system data, you can upgrade or reinstall the Operating System without the fear of losing data.

Upgrading and Reinstalling the Mac Operating System

When you upgrade the Mac Operating System, it installs the latest version of the OS. It’s easy to upgrade the Operating System on your Mac. You simply need to open System Preferences and then click Software Update to upgrade.

Here are the steps to reinstall macOS:

Start your Mac system in macOS Recovery Mode.

Depending upon the type of processor – Apple silicon or Intel processor, follow the instructions below to enter into the macOS Recovery Mode:

Apple silicon: Press the power button to power ON your Mac system and keep it pressed until you see a window with a gear icon labeled as Options. Next, choose Options and click Continue.
Intel processor: Connect your Mac system to the internet (if not connected). Power ON the Mac system. While it starts, instantly press and hold Command (⌘)-R keys simultaneously. Keep the keys pressed until you see an Apple logo or other start-up screen.

By following the above instructions, you’ll be able to launch the macOS Recovery utility window.

From the utility window, choose Reinstall macOS, click Continue, and follow the instructions.

Let the system complete the reinstallation process.

[NOTE]:

Don’t close the lid of your Mac or put it to sleep during the OS reinstallation process.
If you’re prompted to unlock your Mac disk, provide the password you use for logging in to your Mac.
Choose reinstallation on Macintosh HD, if the installer gives you a choice between Macintosh HD or Macintosh HD – Data.

With the above steps, you’ll be able to reinstall the macOS.