On Mon, Jan 1, 2018 at 4:03 AM, David C Brown wrote: > The real puzzle is that the system is* almost *working. MPLAB can > connect to the chip, it can program the chip in both debug and release > modes. The only thing it cannot do is connect to the debug executive. > This and every other reference to the errror on the web suggests that th= e > problem is not in the USB but in the downstream cabling (there are severa= l > reports that shortening the final cables has solved this problem). But > WTF should that be OS dependant? https://msdn.microsoft.com/en-us/library/windows/hardware/ff540207(v=3Dvs.8= 5).aspx WinUSB is a User Mode Driver framework, Kernelspace drivers comply more to timing restrictions etc etc.. So, the userspace timing dictates your bus ti= ming. This is dictates your Near END/ Far END (NEXT/FEXT) crosstalk. IIRC correct= ly, I've gone through this specific problem. Olin Lathrop has had a suggestion for this issue on this ML, a long time back. This did fix the issue for me. There were other issues such as WinUSB.dll getting corrupted and so on. On my veroboards, I've had a series resistor and two capacitors near to the microcontroller. To identify and isolate your problem firsthand, you can write some sample c= ode based on thoughts and ideas from: https://msdn.microsoft.com/en-us/library/windows/hardware/ff540174(v=3Dvs.8= 5).aspx#setup and https://msdn.microsoft.com/en-us/library/windows/hardware/dn376872(v=3Dvs.8= 5).aspx Cheers, Manu --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .