Solution-one option
Have been having lost step problem for ages also, tried everything i could find on the forums, nothing made a difference.
I have a reasonably modern computer running Windows7 (was XP), Mach3 066.
The steps i followed to test this solution were as follows:
Ran a stepper under Mach3 with my std configuration, could actually feel the steps missing every now and then, this was under full step down to 1/32.
Made the system changes (see below)
Without changing Mach3 at all, re-ran the test, this time there was NO indication of missing steps
What I did : Under Windows Control Panel...System and Security...Power Options..Balanced goto Change plan settings...change BOTH boxes to NEVER.
I later fine tuned the Motor Setting in Mach3 on Step to 10us and Direction pulse to 5 us, lower settings also worked but these were optimum for me.
NB: this was a bench test not on a working machine, as mine is down at the minute, but indications are good that this is a solution for me.
Why does this work...not a clue..but it seams to.
I have not seen this on any of the other forums.
Hope this helps and if anyone tries this and it proves workable please let me know.
Doug