I saw in a YouTube that if you press "Ctrl" and move X Y or Z. It will move .001 at a time. I have tried this and it works on this PC. But the PC that my CNC is hooked to will not do the .001 move. If I press "Ctrl" on the CNC-PC the DRO starts moving an will not stop until I press reset.  I tried to reinstall Mach3 with no change. Both PCs are running Mach3 version R3.043.056 W/ Mach2010 screenset. It's not mandatory that I be able to use the .001 move, but I can see where it would come in handy at times. Am I missing a setting somewhere on the CNC-PC?

Check the size of the step you have, it could be you have a large step distance. On the standard screen you can get that by pressing the Tab on your keyboard, no idea if its the same on Gerrys screenset.
Hood

If I press 'Tab' it brings up the MPC Mode.

As said I do not know anything about that screenset but if there is a DRO with step size or something similar then make sure it is set to 0.001  if that is what you want.
Hood

Hood
You right AGAIN
My step increments was set at 6.0000. Changed to .001 But ................... the .0001 changes.  But now I know where I need to look. The problem now is it will not change a whole number like .001 but .0009 or

Thanks

What are your steps per unit, it could be Mach can not physically move 0.001.
Hood

Under Motor Turning
Steps per
X = 1420.682611
Y = 1422.456593
Z = 1602.187457

The X is 0.000704 approx per step so Mach could not move 0.001 exactly as it can only step in increments of 0.000704
Your other axes would be similar.
Hood

With the 2010 Screenset, if you set up your jog increments on the Settings tab, you can cycle through them with the + and - keys while on the Jog Tab. You can use the "End" key to toggle between continuous ans step jog modes.