Some Mac users might want to install a clean MacOS Catalina to Mac. A clean installation is a new beginning, and that is achieved by erasing all data from a Mac hard drive and then performing a clean new installation of MacOS Catalina to the Mac. This type of clean installation feels like getting a new Mac in the sense that there is no data on the device at all, no applications, no user accounts or user data, no system preferences or adjustments, nothing left on the Mac at all, it’s just an installation new empty MacOS Catalina.
A clean installation is not recommended for most Mac users and because the hard disk is erased, potentially causing permanent data loss, so this is really only suitable for advanced users with good reason to format the Mac and restart, or if someone sells the Mac or transfers ownership , or vice versa. Make sure you have a complete backup of your Mac and all important data that was created before continuing.
A clean installation of MacOS Catalina 10.15.x requires the following:
- Mac must be compatible with macOS Catalina
- Has aMacOS Catalina boot drive USB drive been made and ready to use
- Have a complete backup for Mac and all important data created, use Time Machine to back up or other complete backup methods of your choice.
It is important to remember that a clean installation will erase all data and everything on Mac. All personal data, applications, files, and anything on a Mac is deleted in this process. Failure to have adequate data backup can cause permanent data loss, so continue at your own risk.
How to Clean Install MacOS Catalina
Warning: This erases everything on the Mac. Don’t proceed unless you feel comfortable erasing all data and making a backup.
- Complete a full Time Machine backup before starting – don’t skip making a full backup
- Connect the MacOS Catalina drive to the Macs USB port
- Restart the computer
- Immediately hold the OPTION button until the boot selection menu appears on the screen, then select the “Install MacOS Catalina” drive in the boot menu
- On the “macOS Utilities” screen, select “Disk Utility”
- In Disk Utility, select “Macintosh HD” (or the name of the disk to be erased and clean install Catalina), then click the “Erase” button
- Select “Macintosh HD” as the name, then go to “Format” and select APFS, then choose “Delete” – WARNING: THIS PRODUCES ALL DATA ON MAC
- Exit Disk Utility when formatting is finished
- On the ‘macOS Utilities’ screen again, select “Install macOS” from the options
- Select “Macintosh HD” as the destination to install MacOS Catalina, then select “Install” to begin cleaning to install MacOS Catalina
This will start the process of installing MacOS Catalina to Mac, it may take a few moments to complete. Mac will automatically reboot itself during the process, let it finish and don’t interfere with installation.
After a clean Catalina installation is complete, the Mac will boot back to the new and new installation for MacOS Catalina, similar to getting a new computer and turning it on the first time.
Because the Mac is deleted during this process, there will be no personal files, no applications, no preferences, no settings, no adjustments whatsoever on the Mac, it will be if it’s new, which is why this is referred to everyday as ” cleaning “install” in the world of technology.
Basically the Mac will look as if it’s new at this time, and you are free to restore data from a backup, or start anew without restoring or copying anything to the computer again.
Some users can choose to do a clean install as a method of troubleshooting if they often experience problems with their system software. However, if you experience problems with MacOS Catalina, see this troubleshooting guide to help solve macOS Catalina problems.
Did you successfully install a clean MacOS Catalina? Are you using another approach to cleaning Catalina installations? Let us know your thoughts and thoughts in the comments.