Why does "UNKNOWN DEVICE" appear on the display of my Marantz SR6003 when the USB storage device is connected?
- CChristian CarrSep 9, 2025
If "UNKNOWN DEVICE" appears when connecting a USB storage device: * The unit may not recognize the connected device, even if it complies with the USB Mass Storage Class standard. * Ensure the device is not connected through a USB hub, as this is not supported.















