The USB should contain 16-32GB of free space.The user should buy a name-brand flash drive.
To ensure a risk-free procedure certain measure should be taken: Here are the top reasons why the user should choose to Boot Mac from USB: It also helps to repair the Mac disk with Disk Utility and other tools. It provides the user access to the contents of the internal drive, assuming the data is safe and not corrupted. Using an external source like the USB drive helps the user get around the problem. The likeliest of the reason for choosing the boot from the USB method is that your Mac won't start which denies the user access to the computer.
