Apple recently released the MacOS update for all Macs that, as seen, you can install easily and without difficulty, keeping existing data and programs. However, those who want to completely renew their Mac giving a good cleaning can make a clean installation of MacOS (or OSX), which is useful to know how to do even in case of problems to make the Mac come back as new and solve any problem with the computer. A clean installation will erase all the content on the disk, so you need to make sure that you have a backup copy of your important files, photos and documents, before proceeding.
First of all you need to burn MacOS to a USB drive that has at least 8 GB of space.
The USB stick must be formatted by opening Disk Utility, which is located in the Utilities folder under Applications .
When formatting the USB drive, select the Mac OS Extended (Journaled) option as the format type and leave the name " Untitled ".
Then you need to download the OSX Mac OS installation file from the Mac App Store and stop the automatic update immediately.
The easiest way to burn MacOS to a USB disk and to automate creation is through a free application called DiskMaker X.
Download the DiskMaker X program and drag the icon into the Applications folder.
Insert the formatted USB stick into your computer, start DiskMaker X, choose MacOS from the list of options, and let it work for a while without doing anything else.
Alternatively you can also use the Disk Creator program which is very similar and easy to use.
The creation of a Mac system installation USB stick can also be done manually via Terminal .
After downloading OSX MacOS and formatting the USB drive (with the name Untitled ), open the Terminal application, paste and run the following command in the window:
sudo / Applications / Install \ macOS \ Catalina.app/Contents/Resources/createinstallmedia --volume / Volumes / Catalina / (if the system is Catalina).
You will be asked to enter your password and installation support will be created.
At this point, to do the clean installation of MacOS, leave the USB drive connected to the Mac, restart the computer and, during startup, hold the ALT key to start the installation file saved on the USB stick.
Before proceeding, initialize the main hard disk partition from the Disk Utility menu.
This USB stick can be used on any Mac to install MacOS cleanly and from scratch.
After installation, you can start restoring programs and settings using the Time Machine application backup.
NOTE: A Mac installation USB stick can also be created from Windows
