Reinstall your computer’s original version of macOS (including available updates): Press and hold Shift-Option-Command-R. Reinstall the version of macOS stored on your computer’s built-in recovery volume: Press and hold Command-R. In the Recovery app window, select Reinstall macOS Big Sur, then click Continue. Follow the onscreen instructions. I can see the answers suggested here on how to accomplish that: Mac stuck in restart cycle after failed macOS Catalina update. However, when trying to recover / reinstall macOS - the installer also tells me - you don’t have enough free space to reinstall macOS.
macOS Catalina is Apple's next-generation desktop operating system that comes with tons of improvements and new features. In reality, Catalina is not a significant update over Mojave, but it has a few cool things that we have been demanding for years. macOS Catalina has been available for testing purposes for months, giving users a glimpse of what's including in the final release.
As a beta form, macOS Catalina is still a little bit buggy, but it is still worth your time. If you are thrilled to test out its new features, then you can make a clean install of macOS Catalina manually, which is more challenging than official upgrade. Following this method, all of your data will be wiped and you can set up your Mac as a new device. So, it's a good idea to have a recent backup of your machine before moving ahead.
Part 1: Download macOS Catalina Public Beta
Official system upgrade is still not available for Mac users currently so you have to download the macOS Catalina DMG and make a bootable USB for installation. For official upgrade, the process is so much easily, which only takes for 3-5 clicks and wait for the upgrade to be completed. However, in this case, it is more harder for manually installation.
Step 1:Go to Apple Beta Software Program and sign in with Apple ID. You have to agree the terms before proceeding.
Step 2: The next step is choose the beta program you want to enroll. Choose macOS this time. After that, you backup the Mac with Time Machine.
Step 3: Download macOS Public Betat Access Utility, which reuqires time machine devcie to be connected. This makes sure all your data is safe place. Install the utility and complete the enrollment.
Step 4: Go to SystemPreferrence -> Software Update and click Download button to download the release.
Part 2: Create a Bootable macOS Catalina USB Install Drive
Before we begin, make sure you now have a USB flash drive by your side. We recommend you get a USB flash drive with a USB-C port. That makes sense, seeing that all Mac models now support Thunderbolt ports (USB-C).
Method 1: Terminal (Mac Only)
Step 1: Once the download is complete, the installer should automatically fire up. From here, just close the installer on your Mac and proceed with the next steps.
Step 2: Launch Finder, then select Applications, and right-click the Install macOS Catalina Beta file you downloaded earlier.
Step 3: From here, select Show Package Contents from the drop-down menu, then open Contents and hit Resources.
Step 4: Open Terminal, then enter sudo and hit the Space key. After that, drag the macOS Catalina installer file and drop it into Terminal.
Step 5: Enter –volume in Terminal and hit the Space key. Now, head over to Finder >Go >Go To Folder. From here, enter /Volumes in the 'Go To Folder' section and hit Go to proceed.
Step 6: Connect your USB drive to your machine and it should show up in Finder (in macOS Catalina, Apple removed iTunes in favor of 3 separate apps; Apple Music, Apple Podcasts, and the Apple TV app).
Step 7: Move your USB flash drive into Terminal and hit the Return key. Input a 'y' and proceed with pressing the Enter key. This will move macOS Catalina installer files to the USB flash drive (the process may take several minutes).
if you encounter any problems during the process, try formatting the USB drive to APFS.
Method 2: UUByte DMG Editor (For PC and Mac)
It is a much more complicated process when using Terminal app. If you don't like or do not have a Mac at hand, then UUByte DMG Editor is the best solution out there. It works on PC and Mac. Also, it has a GUI and easy to get started for creating bootable macOS Catalina USB installer.
Step 1: Download macOS Catalina DMG file from here.
Step 2: Install UUByte DMG Editor on a Windows PC or Mac and insert a USB drive after that.
Step 3: Click 'Next' button at Burn column and you will be lead to a new window. From there, please import macOS Catalina DMG file into it and select the USB drive.
Step 4: Click 'Burn' button and wait for about several minutes. Then you will get a bootable macOS Catalina USB drive.
Part 3: Boot Mac from USB and Start Installing macOS Catalina
Once you have a bootable USB install drive for macOS Catalina, you now can boot from it and then start installing macOS on your mac and set up it as new.
Step 1: Connect the macOS Catalina USB install drive to your Mac and then reboot your machine.
Step 2: Hold down the Option key. Keep the button pressed until you see the boot menu. From here, select the macOS Catalina USB installer drive you created earlier to boot your Mac from.
Step 3: When your Mac finishes booting up, follow the on-screen instructions to complete the setup. Once you are done, you will be able to restore your Mac from a Time Machine backup.
The Bottom Line
Creating macOS Catalina installation USB is a smart move if you want to use your Mac as a new device and keep it running smoothly. Hope that our guide works for you. Keep in mind that macOS Catalina is still in its early stages, so play it carefully with caution.
This page covers the full process of how to update and install the latest macOS Big Sur, Catalina, Mojave, etc. on Mac without losing any data. If you need a detailed guide, follow through this page to get the desired macOS installed on your computer now:
| Workable Solutions | Step-by-step Troubleshooting |
|---|---|
| Phrase 1. Preparations | 2GB+ memory and 9GB+ storage space left on Mac > 45% + battery > Connect to internet...Full steps |
| Phrase 2. Change a USB port | Start Mac from macOS Recovery > Select 'Reinstall macOS' > 'Continue'...Full steps |
| Phrase 3. Recover Lost Data | After macOS installation, run EaseUS Mac data recovery software > Scan and recover lost data...Full steps |
Applies To: macOS Big Sur, macOS Catalina, macOS Mojave, macOS High Sierra, macOS Sierra, or earlier Mac operating systems
The need to update or reinstall your macOS always follow the release of a new operating system, the slow performance of your Mac, or a system crash. When it comes to reinstalling macOS, users biggest concern is losing data on their computer.
The good news is that, if you follow the instructions strictly to update your Mac Operating System, the chance to lose data on your Mac is quite slim, since a reinstallation just needs to create a new copy of the OS, your existing files stored on your Mac won't be lost. Thus, as long as you don't choose to erase your startup disk during the reinstallation, you won't lose files. However, you know what 'Slim' means - it's not 100% safe and is still at the risk of losing some data.
Then how to reinstall macOS without any data loss? To provide a double guarantee to the precious data on your Mac, you can make a copy of the files on your Mac before you perform the reinstallation, or equip your Mac with a data recovery tool that can rescue your data after the reinstallation.
Preparations you Need to Make Before You Reinstall macOS
To reinstall macOS on your computer smoothly. Follow the tips below to prepare your Mac ready for the new macOS update now:
- Leave at least 2GB memory and 8.8 GB storage space on your Mac
- Leave at least 45% battery on your Mac
- Connect Mac to the internet or WiFi
- Update your Mac Apps to the latest versions
- Backup all your personal data and even create backups for your present Mac data through Time Machine
Remember to back up your Mac to an external hard drive for preventing system update failure or unexpected troubles from happening. Then follow the detailed guide below to reinstall Mac OS via macOS Recovery mode, which enables you to reinstall macOS, restore your files from Time Machine, repair or erase a disk, and more.
How to Update & Reinstall macOS Without Losing Data
*Print this page or open this page on another device so you can refer to it later.
Step 1. Start up your Mac from macOS Recovery
- Turn on your Mac and immediately press and hold 'Command + R', 'Option + Command + R', or 'Shift + Option + Command + R'.
- Release the keys when the Apple logo, a spinning globe, or a pop-up for a firmware password appears.
Step 2. Select 'Reinstall macOS' from the Utilities Window and click 'Continue'.
Step 3. Follow the onscreen instructions to select the hard drive you want to install the OS on and start the installation.
Step 4. Don't put your Mac to sleep mode or close its lid during the installation. It's normal to see your Mac restart several times or the screen is white while you reinstall the Mac OS. Just wait patiently for the process to finish.
If data loss occurred after you reinstalled macOS, you can follow the next part to recover your missing files.
Recover Lost Data After macOS Reinstallation
If you have backed up your Mac before the reinstallation, you can retrieve your data from Time Machine, an external hard drive, or somewhere else, depending on the way you used to make the backup. If you haven't created any backups for your Mac, then you'll need the professional Mac data recovery software tool - EaseUS Data Recovery Wizard, to perform data recovery. With the help of this tool, you can easily recover the data lost due to macOS reinstallation:
Step 1. Select a location and start scanning
Reinstall Mac Os Catalina From Recovery Mode
Launch EaseUS Data Recovery Wizard, hover on the location where you lost data, then click 'Scan'.
Step 2. Preview and select the files
Wait until the scanning completes. You can use Filter or search bar to find lost files.
Step 3. Recover lost data
How To Reinstall Mac Os X Catalina
Then choose a location to save the recovered data, and click 'OK'. You should store the data in another place instead of the original one.
There are lots of data recovery tools available. But EaseUS Data Recovery Wizard, one of the best Mac data recovery tools, is our pick. It fully supports all macOS systems including the newest Big Sur, Catalina, Mojave, High Sierra, Sierra, EI Capitan, Yosemite etc. It allows you to restore all lost data with simple clicks. Office files, music, videos, emails or other archives can all be restored on your own.