If you receive this error message A device attached to the system is not functioning, here are a few things you may try. It is quite possible that the attached device is not working for one of these reasons:

  1. USB or external device is switched off, or connected improperly
  2. The external device and drive types are incompatible
  3. The external device is not properly inserted in the drive or connected to the port
  4. The drive door is open
  5. The external device is not properly formatted.

Correct the problem by addressing the above possibilities and try again running your command again.