External storage device formating error?
You could easily wipe the drive and start fresh - use care that disk 3 is really the disk you wish to erase everything.

diskutil eraseDisk JHFS+ UntitledUFS disk3


If that fails, you likely have a hardware error (unless the failure is your OS or not using an account with sudo permissions). If that succeeds, you could then use Disk Utility to rename things as you please or learn more about diskutil and use it to rename / repartition / reformat the drive going forward.