I have been using Mach 3 since 2008, when I built my first CNC router table. The software that I use to create tool paths include MeshCAM Art, Corel Draw, and LazyCAM Pro. I have not learned much, in terms of memorizing the various G code command set. So, I am unsure how to address a problem that has recently come up. In the past, any time I was running Mach 3 driving the machine (with either a *.NC or *.tap file loaded into Mach 3), and needed to pause program execution, I simply pressed the space bar. Which paused the machine. If I needed to make changes to things like cutting depth, etc. I would then click on the Rewind button, and click on the Router button, (to turn OFF the router). Then I would go into LazyCAM to make the needed changes. (in the case of *.tap files). However, when I attempt to do this now, I receive the following message "Unable to reverse execution, No jogging available". Any attempts at entering manual commands have no effect. Except to hit the Escape Key on the keyboard, which stops everything. Clicking the Reset button in Mach 3, runs the initialization script with the default settings that Mach 3 came with. (It loads, and executes a series of G codes which set up various things such as Metric or Inch measurement preferences, etc.) My question is this: Is there a setting in Mach 3, which prevents Rewinding a G code file during it's execution? Or perhaps a G code command, which does this? SOMETHING HAS CHANGED, and I need help understanding WHAT!
Any help with this problem will be greatly appreciated!
Thanks! -Michael

Try using a backup xml file from a time before the problem started. I find that I have to do this once in a while when the space bar stops working or the F5 spindle toggle drops out. I believe that it is a corruption of the xml file, but what do I know?

Mike