I'm working on a top-sown assembly model and having some crash issues. My main sketches are based on the assembly planes and offset planes as needed to fully define the structure. I've added two components to the assembly, and copied one of them for a right-hand part. Those three parts form a sub-assembly that I want to save externally.

When I attempt to create the sub-assembly, all is well until the save externally step. "Solidworks has encountered an error and needs to close" is the last thing I see. The first time I selected all three components, right-click and form new sub-assembly. The second time I selected one component to create the sub-assembly and then used drag to move the other two parts in. Same result.

All parts are fully constrained/mated (not fixed) and contain sketch entities converted from the overall 3D sketch, two of the parts are sweeps so the internal sketches are the path and profile.

Anyone seen/solved this before?