Thanks for your reply.

I don't think the ESS is the problem, I have tried again running mach3 in PrinterPort mode, and without any using any Motion Conrol, by Mach3 Menu > Function Cfg's > Reset Device Sel.., restarting mach3 and selecting No Device.

I can still get the same error.

As you say it's worth a try using an order version of mach3 for testing to see if I still get the error.

But from what I have been told I can only use the ESS with Mach3 R3.043.062 and newer.

Best Regards.