I have downloaded the latest version of Mach 3.  All features appear to work except MDI. After entering an instruction and then hitting enter, the instruction disappears, no movement of the machine takes place and the machine becomes disabled.  In order to get the machine to jog again I have to estop and then rest.  Any help would be appreciated.  Thanks

Are you using a smooth stepper? If so, switch on your machine, open up mach 3, accept re-set if it is flashing, then before you do anything else, load a G code programe, (Any program), then try to run a command from MDI.

Thanks-Didn't know I needed a program loaded.  Is that always the case?

It shouldn't be the case, but I had the same problem as you when I converted from parallel port to smooth stepper around 10 months ago. Not everyone is seeing this problem and I do not know why some are. The good news is that the work around is very reliable and I have been using the machine daily without any problems as long as I start off with a G code program loaded.

Perhaps if others are experiencing the same thing and they report it on the forum, it may throw further light on the root cause.

Thanks again-it is a reliable work around.  I'm actually not using smooth stepper.  My interface is through an add on port by netMos.  I also have closed loop feedback through SoundLogic boards.  Not sure if any of those relate.