Catalina Reinstall

The only issue I still have is after reinstalling many of the apps, I need to figure out where previous scripts and preferences are stored. As an aside, Catalina will not show Library as a View option in Finder. I did see on your web site an option: once Library is opened using the Option, create an alias. Thank you again!
Once you complete the steps, you can now insert the USB flash drive on your Mac computer to install, reinstall, or upgrade the operating system to the latest macOS version, which can be Sierra, Catalina, Big Sur, or higher.

If you have installed Big Sur, Catalina, Mojave or earlier versions, you may have to reinstall macOS for following reasons:

Reinstall When There is New macOS Version Available

Prepare Your Mac for Reinstallation. Make enough room for Big Sur or Catalina reinstallation, at least 36GB, so the reinstallation process won't pause or stopped for insufficient space. Also, quit all apps or programs under work, so your Mac is fully geared to reinstall.

Apple keeps working constantly to fix bugs, make performance tweaks, add new features or enhance coding. Therefore, doubtless, there will be new versions of macOS available to upgrade and reinstall.

Your Mac is Running Slow

Catalina Installer Download Dmg

As we all know, for no specific reason, system reinstallation can magically solve a slow Mac in most cases.

Your System Keeps Crashing or Works Improperly

When you continuously see error messages appear on your mac, or your programs randomly crash/freeze for no reason, like FaceTime won't work, Contacts or Calendar shows a delay or mess, blue teeth or WiFi won't connect…Then, you have a good reason to reinstall macOS.

You are Going to Sell the Mac

In the case that you want to sell your mac, besides erasing all your personal data and traces on the mac, you will need to reinstall macOS as well.

It is not complicate to reinstall macOS Big Sur or Catalina, but if you want to reinstall macOS without losing data, there are 3 steps you must follow.

Recover Files after macOS Reinstall

Recover data lost due to macOS reinstallation, upgrade, downgrade
Recover data lost due to accident deletion, formatting, etc.
Restore data from both internal and external storage device
Recover videos, audios, images, documents, and other 200+ files
5 recovery modes to find files back easily
High recovery rate
Support Big Sur, Catalina, Mojave and earlier

Free Download

3 Steps to Reinstall macOS Big Sur or Catalina without Losing Data

We all save tons of data on our Mac, so when we decide to reinstall macOS Big Sur/Catalina, the top concern always goes to “will I lost everything if I reinstall macOS”. In fact, reinstallation of macOS doesn’t necessarily cause lost data, it just create a new copy, your existing files and data saved in programs won't be altered or deleted. But just in case of bad luck, we need to do some work on BACKUP, this is crucial for macOS reinstallation without losing data.

Step 1. Prepare Your Mac for Reinstallation.

Make enough room for Big Sur or Catalina reinstallation, at least 36GB, so the reinstallation process won't pause or stopped for insufficient space.
Also, quit all apps or programs under work, so your Mac is fully geared to reinstall.
Check drive conditions. Open Disk Utility and perform the Frist Aid on your hard drive where to reinstall the macOS to make sure your drive is in good condition for reinstallation.

Step 2. Backup All Your Files for macOS Install (Crucial)

Backup is an indispensable step involved in the macOS reinstallation, here are several options to backup your data.

Option One: Using Time Machine

Go to Finder>Application, launch Time Machine and choose “Set Up Time Machine”.
Click “Select Backup Disk” to choose an external hard drive to back up the files.
Then Check the box before “Back Up Automatically”. Also, you can adjust the backup setting in menu “Options”.

If this is the first time you use Time Machine to backup, wait patiently for Time Machine to complete the backup, it will prompt the notification once finishes.

Option Two: Using Hard Drive

Connect your hard drive to Mac.
Open Finder to check if your hard drive is present under “Devices”.
Create a new folder, copy and paste or directly move the items you want to save from Mac to this folder.
Finally, eject your hard drive.

Option Three: Using iCloud Service (Backup Desk and Documents Folders)

Go to Finder>System Preference, click on “iCloud” to bring up its main interface.
Click the “Options” button for “iCloud”, and check the box before “Desktop and Documents Folders”, then click on “Done”.

Most of our mac users prefer to backup all files but apps. So, to save you from troubles of lost data due to macOS reinstallation, you are recommended to keep records of what apps you have installed, the account and password, also, you can take screenshots of the settings.

Step 3. Reinstall macOS Big Sur or Catalina without Losing Data.

Option #1: Reinstall macOS without Losing Data From Internet Recovery

Click the Apple icon>Restart.
Hold down the key combination: Command+R, you will see the Apple logo.
Then choose “Reinstall macOS Big Sur” from utilities window and click “Continue”.
Select your hard drive, click “Install” and wait for end of reinstallation.

Option #2 Reinstall macOS without Losing Data From USB

Download the macOS Big Sur install from Mac App Store onto your Mac;
Then connect the USB flash drive to your Mac;
Open Disk Utility program on your Mac, choose the USB flash drive and click Erase to have a clean drive for the reinstallation;
Open Terminal, copy and paste sudo /Applications/Install macOS Big Sur.app/Contents/Resources/createinstallmedia;
Then add the volume of usb flash drive: --volume /Volumes/MyVolume, replace MyVolume with your usb flash drive name, mine is Untitled;
Press Enter, input password and wait for the process to finish;
Quit Terminal, restart your Mac, hold Command+R when starting Mac until you see the apple logo;
Login into your Mac with password, go to the menu bar>Utilities>Startup Security Utility, enter password again;
Choose Medium Security under Secure Boot and allow booting from external media;
Restart your Mac, in the same time, hold the Option key;
Choose Install macOS Big Sur, click Next and input password, choose Install macOS, continue to finish mac reinstallation from usb.

Mac Won't Turn on after Update to macOS Big Sur?

Here are 10 solutions to fix 'Mac won't turn on after update to macOS Big Sur, Catalina or other versions'.

What if You Lost Data After macOS Big Sur Reinstallation?

However, losing data after reinstallation still happens. It may result from a interrupted installation (power-off/poor internet connection), corrupt setup, insufficient space or improper actions. Then, what to do if you lost data after reinstallation? Here are 2 methods.

Method 1: Use Cisdem Data Recovery to Recover Data

In the case you didn’t do backup before reinstallation, you will need a dedication data recovery program to find the lost data for you.

Here we recommend Cisdem Data Recovery, a powerful mac program allowing users to recover lost/deleted/corrupted/formatted files from a wide range of external or internal storage devices, no matter the file is lost due to human errors, power-off, reinstallation, upgrade, virus attack or disk crash.

Main Features of Cisdem Data Recovery

Recover files lost due to OS reinstallation, upgrade, downgrade;
Recover deleted, formatted and lost files;
Restore files from internal and external hard drive, USB, SD Card, flash drive, etc.;
Restore videos, audios, images, documents, archives, 200+ types;
5 recovery modes: Basic, External Drive, Formatted Drive, Trash, Advanced;
Preview files before recovery;
Fast scanning and recovery;

Steps to Recover Lost Data after MacOS Reinstallation

Download and install Cisdem Data Recovery on Mac.
Free Download
Choose a Recovery Mode according to your need.
If you want an efficient recovery, choose “Basic Data Recovery”, if you want to recover files with a higher success rate, try “Advanced Data Recovery”.
Select the hard drive where you originally stored the files on mac. Then click “Scan”.
Check and preview files found by Cisdem Data Recovery.
Select files to recover.
Check the box before files that you want to recover, then click “Recover” to find back the lost data caused by reinstallation.

Method 2: Use Time Machine to Recover Data with Backup

If you have backed up your files on mac, you can use Time Machine to restore the lost data.

Step1. Go to Finder>Applications>Time Machine, launch it and choose “Enter Time Machine”.
Step2. In the popped-up window, use the arrows and timeline to browse the local snapshots and backups.
Step3. Find the deleted files, then click “Restore” to recover the lost data caused by reinstallation.

Conclusion

The key to reinstall mac OS Big Sur, Catalina or Mojave without losing data is the backup, since no one can guarantee all data will be perfectly maintained after macOS reinstallation. However, if we unfortunately lost files after macOS reinstallation, Time Machine or Cisdem Data Recovery is helpful to recover them back.

So, do you have any other tips to reinstall macOS without losing data? Please share with more of our mac users.

How to Reinstall macOS on Your Computer

If your Mac has been having problems or behaving erratically as of late, it might be time for a fresh install of macOS using Recovery mode and Disk Utility. A new install may also be useful if you have plans to give away or sell your Mac. In this case, you’ll want to remove your personal data and conduct a factory reset before your Mac leaves your possession.

Here’s how to go about reinstalling macOS on your computer using Recovery mode and macOS Utilities.

How Do I Reinstall macOS?

Important: Should You Back Up Your Data Before Reinstalling macOS?

Even if you’ll be keeping your computer in your possession and won’t be wiping data, it’s always a good idea to back up your Mac before reinstalling macOS. That way, in the event of an error, you can be sure your private documents, pictures, and more will remain safe. Backups can be performed using either a separate hard drive or the cloud.

Before Your Begin: Which macOS Version Do You Want Reinstalled?

The following instructions will help you reinstall the latest macOS version that’s been installed on your Mac. Please note that if you prefer to install the latest compatible version of macOS or alternatively, the first version of macOS that originally came with your Mac, you should search for those specific instructions.

Follow These Steps

Step 1: Start by entering Recovery mode on your Mac. To do this, navigate to the Apple icon in the top left corner of your screen, and click “Restart…”. This will shut down your computer and immediately start it back up again. As soon as you hear your computer start to come back on, press and hold down one of the following key combinations:

Catalina Reinstall Os

On Intel Macs: Command + R
On M1 Macs: Power button*

*Hold the power button until you see a startup window appear with options available, and click “Options” and then “Continue”.

Catalina Install Mac

Step 2: You’ll see the macOS Utilities window open. For those wiping their disk, navigate to “Disk Utility” and then click “Continue”. If you do not plan to wipe your disk, pause here and move on to Step 8.

Step 3: Erase the desired volume. For Macs with any operating system older than Catalina, simply delete the volume titled Macintosh HD. For Macs that have Catalina or any operating system that came after Catalina, you’ll be required to delete the following two volumes:

Macintosh HD
Macintosh HD-Data

Catalina Install Usb

First, delete Macintosh HD-Data. Next, delete Macintosh HD.

Step 4: If your current macOS version is Catalina, Mojave, Big Sur, or (in most cases) High Sierra, select the format APFS. If your current macOS version is older than these, select the macOS Extended (Journaled) format.

Step 5: For the Scheme, choose GUID Partition Table. Keep in mind that if you only have the volume selected, the Scheme won’t be something you have to worry choose.

Step 6: Select “Erase and wait”.

Step 7: Press Command + Q to quit. Alternatively, select “Disk Utility” and then click “Quit Disk Utility”.

Step 8: Looking at the Utilities window before you (note: if you’ve just wiped your computer following the above steps 2-7, the Utilities window will be appearing for the second time). In either case, select “Reinstall macOS” and wait until the process has completed.

Use the steps above to reinstall macOS on any Mac. Keep in mind that this process should be completed during a time in which you can devote your full attention to it. While you won’t have to stare at your screen throughout the actual reinstallation process, you should be nearby in the event that any troubleshooting is needed.