Using the latest lockdown version with G100 plugin and a custom plugin that I wrote to handle a serial pendent. The "PAUSE" function was working OK until today. The system will just not pause. I unloaded the custom plugin that I wrote thinking that this was the problem, however the the pause still will not work. I have tried both the System pause and button 1001. Any thoughts?

From what I have heard from others using the G100 it is best to find a Rev of Mach that works well then stick to it, that is if you are using the G100 for motion control.
 Having said that there were problems with the FeedHold in earlier versions and the remedy was to press the FeedHold twice, doesnt seem to be an issue for me in the later versions but might be worth a try to see.
Hood

Nope, been down that path. It just refuses to feedhold. Funny thing is that it worked for a couple of weeks and then just quit.

Did you try reverting to the previous version that you were using?
Hood