It is unlikely that the DLLs in two very different systems are corrupted in the same way. Although I describe myself as a hobbyist I worked for 40 years designing digital logic and I know a great deal about the problems that crosstalk can cause. I have done more tests with the 5cm cable, keeping clock and data apart. In both working and failing scenes the edge speed of the clock is tens of nano seconds. __________________________________________ David C Brown 43 Bings Road Whaley Bridge High Peak Phone: 01663 733236 Derbyshire eMail: dcb.home@gmail.com SK23 7ND web: www.bings-knowle.co.uk/dcb *Sent from my etch-a-sketch* On 4 January 2018 at 12:49, Manu Abraham wrote: > On Thu, Jan 4, 2018 at 5:49 PM, David C Brown wrote: > > I have tested the same set up on a desktop machine running Win7 and it > > fails in exactly the same way. > > I have also tested it with the shortest possible cable - less than 5cm= - > > and still get the failure so I doubt that cross-talk is the problem.d > > The logical conclusion is that, whatever Microchip say, MPLAP8.92 is n= ot > > fully compatible with Win7. > > For XP emulators the lord be thanked :-) > > I dont think it's a compatibility issue at all. Either something is > wrong in your system > (DLL corruption and or whatever), or there is still crosstalk, i must > say. There's no > logic in the compatibility issue. > > Another way to debug (painful way) comparing USB messages being sent in > both > the situations. > > http://www.usblyzer.com/ > > > Cheers, > > Manu > -- > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > --=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 .