Please ensure that you are using the supplied blue USB cable.
The following information might be helpful in determining what is happening:
- The PC operating system
- Whether the PC is a desktop or laptop
- Which USB ports are being used (front or rear for a desktop, USB 2.0 or USB 3.0)
- Whether a powered USB hub is being used
- If there are any other devices connected to the USB ports
Having to unplug the USB cable indicates that the driver still has a lock on the device.