(Windows 10) If you have used the Arduino IDEs prior to getting a MAXREFDES100HDK, the serial driver will claim the USB device and you will be presented with a serial port and no USB flash. So you will not be able to use the HDK because the Arduino serial driver has grabbed the USB serial endpoint, and ignored the MSC (mass-storage) endpoint in the composite device the HDK presents.{{/media/uploads/zaphodikus/capture.jpg}} Simply right click the serial port in device manager, and totally remove the device&drivers, no reboot needed, you may need to do this more than once. Replug the MAXREFDES100HDK - using the port labelled HDK, and get mbed'ing! {{https://pbs.twimg.com/media/DqgX3WHXQAA7S7S.jpg|MAXREFDES100HDK}} Next, install the correct firmware on the HDK for your target - see [[https://os.mbed.com/teams/MaximIntegrated/wiki/MAXREFDES100HDK#firmware-images]]