What to do if I get the message "The part is not attached to any part holder"?
When you get this message, it means that TopSolid was unable to attach your part to a machine element (table, chuck or any of the part holders defined on your machine).
This can happen, for example, when you cancel part positioning.
To define a new part holder, go to Equipment > Machine tool > Set Part on Machine.
Then select the part holder attached to your part: