People who create a USB stick are doing so because they want to be able to boot from the sick and completely erase the hard drive to do a clean install.

How to make a bootable USB drive If you're trying to install a new operating system or flash your BIOS, you're going to need a bootable USB drive - here's how to make one.

Related: How to create Windows bootable USB Flash Drive from ISO 2] Create installer with Boot Camp Assistant Plug in the USB driv e to the MacBook port.

Disable USB Legacy Support The computer may boot correctly with the external hard drive connected if USB Legacy Support is disabled.