I have a multi-body 'master' part.  I wanted to create a new part file using one of the bodies. I did so using by right clicking one of the bodies and selecting "insert into new part..."

The new part opens fine and am able to work with it for a period of time including saving it, but eventually when I try to save the new part Solidworks either:

1) Gives the error: "An unknown error occured while accessing..." and prevents me from saving the part.

2) Crashes

I've been through this process three times and am wondering if there is another way to create a part from a body in a master part.

I'm using SW 2017 SP3