Wipe off the USB drive
Windows
Mac
Insert the USB drive.
Open Terminal.
Find the location of the USB drive:
Type in the following command to list all the drives. This should show a listing of the different drives.
diskutil list
Find your USB drive in the list (it will be something like
/dev/diskX (external, physical)where X is the number assigned to your USB drive. Look at the size of the drive to verify that it is the correct drive.
Before erasing, you may need to unmount the drive.
Erase the USB drive:
Click the Erase button at the top of the window.
Type a label for the drive into the Name field.
In the Format field, select
MS-DOS (FAT).Click the Erase button.
