How to Install MacOS High Sierra from USB

Before you begin the process of installing MacOS High Sierra from a bootable USB installer, it is crucial that you take the time to back up your important data and files. A clean install erases everything on the Mac, including all data, files, photos, movies, and apps. This is why it's essential to have a backup plan in place before proceeding.

To create a bootable USB installer for MacOS High Sierra, follow these steps:

1. Download the MacOS High Sierra installer from the App Store or create a bootable installer drive using the built-in macOS utility.

2. Connect your USB drive and open Disk Utility on your Mac.

3. Select the USB drive and click 'Erase' to format it as a single partition.

4. Click 'Done' to confirm the erase operation.

5. Open Terminal and use the `sudo` command to create a bootable installer drive for High Sierra.

After creating the bootable installer, you can now install MacOS High Sierra from USB. To do this:

1. Insert the USB drive into your Mac's USB port.

2. Restart your Mac and hold down the 'Option (⌥)' key while powering it on.

3. Select the USB drive as the boot device from the startup menu.

4. Follow the on-screen instructions to install MacOS High Sierra onto your Mac.

In summary, a clean install of MacOS High Sierra requires careful planning and execution, including creating a backup of all important data and files before erasing the Mac's hard drive. This process is best suited for advanced users who are familiar with manual backups and restoration procedures.

How to install macos high sierra from usb