There is a discussion on that topic here: Restart part way through It might be more trouble than it is worth. You are essentially creating a new job file. Since you are working a 3d file I am assuming that you missed steps on the roughing pass. You “could” change the tool speeds in Aspire and then way slow it down in Carbide Motion when you get to the area where it faulted. I feel your pain. That’s a big chunk of walnut you’re working with.