I found this to be an interesting read: Mach3 Truncates G-code
Check your Mach license and see if it is legitimate...
If you bought from Paul Henrik (Deepgroove) check your license file! You may be the victim of a scam and not know it yet.
Is it registered to "Paul Henrik"? If so it will stop working whenever you update software. Contact Art or Artsoft immediately for a legitimate replacement.
Those of you who might have had them stop working, now you know why. If it was purchased from Deepgroove contact Artsoft immediately and ask for a new file.