Routinely, if I open an existing rhino file and then select a model and a toolpath and then ask to recalculate the pre-existing toolpath I will get an error msg: "this toolpath contains no valid search path to the cutter tool!"
These are toolpaths that have worked just fine previously, which have been sent to post processor, and for which a tool has obviously been previously assigned.

So, I'm not sure why this happens.

Reason for wanting to do this is that I want to review the settings that I previously used in the production of a particular toolpath.

S. W.