Well I decided to try deleting the registry key and restarting Mastercam so far this has fixed the issue.

Wow, I am glad someone else is having this issue we have four programmers and three of us are having this issue one is not. It happens in lathe and on a transform tool path in milling, I did find that if I turn the tool display off then back on before starting the back plot it does not crash. I have done all the ideas shown above except for the deleting the registry file I will try that next chance I get and see if that corrects the issue. It would be nice to hear if more people are having this issue, my assumption it is a graphics card/ graphic card driver issue.