Hi
@chucktilbury
I loaded your file into Masso and ran it on my setup.
Everything seems to run exactly as it should. At the end if the file the M30 sends it back to the beginning of the file.
The spindle has stopped and the DRO's read X0,Y0, Z1
Pressing the cycle start runs the file again and each time it runs exactly the same, ending by rewinding the file with DRO's reading X0,Y0, Z1
Guy is correct that there needs to be a line after the M30 for it to work. The very last line of the Gcode file is ignored so just hit Enter to create a blank line as you did with this file and it will work ok.
What version software are you running, I tested using the latest release v3.42 Mill.
Cheers
Peter