If you are using Windows, please check out the following Video: https://www.youtube.com/watch?v=k-DMAfhQi_c
Ensure the USB Key Format is FAT32
> Right Click on the USB Key
> Select Format
> File System FAT32
> Click on Start to Format
If you are using MAC, check out the following video:
https://youtu.be/I_AGrGUnx0M
Ensure the USB Key Format is MS-DOS (FAT)
> Open the “Disk Utility” app
> Select the USB Key
> Click on “Erase”
> Select Format “MS-DOS (FAT)”
> Click on “Erase” to start formatting the USB Key
