Thanks Doug, I have started a PM conversation with Adam. I was down at the observatory on the weekend and checked all the cables. I don't have it going through any hubs it is direct to the computer on the scope. This problem has only arisen since the update of the drivers and Maxim DL. Colin, I checked all the USB devices and all was as I had setup many months ago. Every USB has been turned off for power management. I don't run Windows update at all as a rule. It usually ends in disaster, not the guilty culprit this time around. Happy to hear any other suggestions. Should I upgrade again to the latest version of MaximDL? I have paid for it, I just don't think it will work at present.