Try the following procedure.
- Turn off the Sound Bar.
- Remove and reconnect the USB device.
- Make sure the USB device is securely connected to the (USB) port.
- If the USB device is connected via a USB hub, disconnect the USB device from the hub and connect it directly to the Sound Bar Speaker.
- When connecting a Walkman or smartphone, the internal storage or external storage (such as a memory card) may not be recognized.
- Turn on the Sound Bar.
Issue is resolved
The issue was caused by connecting the USB device via a USB hub, or a temporary malfunction occured on the Sound Bar Speaker.