It came with Mountain Lion (OS X 10.8), and with each upgrade, I always perform a clean install because I prefer starting without clutter.
There are many guides on how to create a bootable installer, but for doing this I’ll follow the instructions from Apple on how to create a bootable installer for macOS, along with how to erase a disk for Mac, since I will do a clean installation.
I will use a 16 GB USB drive labeled “INSTALLER” for creating my bootable drive.
And these are the instructions:
- Download macOS Catalina from the Mac App Store
- Once downloaded run the following command:
$ sudo /Applications/Install\ macOS\ Catalina.app/Contents/Resources/createinstallmedia --volume /Volumes/INSTALLER
- Restart your Mac and press the alt-option key as soon as it restarts, so you are prompted to select a Startup Disk
- Select the macOS Catalina Installer
- Select Disk Utility and click Continue
- Choose View > Show All Devices from the menu bar, and select APPLE SSD
- Click Erase and assign these settings:
- Name: APPLE SSD
- Format: APFS
- Scheme: GUID Partition Map
- Click Erase
- When done, quit Disk Utility
- Select Install macOS from macOS Utilities, and click Continue
- To set up the installation of macOS Catalina, click Continue
- Agree to the terms of the software license agreement
- Click Agree on the next prompt
- Select APPLE SSD and click Install
- Sit back and relax
Once the installation is done, you’ll be asked to configure your Mac.
And that’s it! You’ll have a “brand new” Mac!