I have a large assembly that is using a C-Channel Structural steel shape in a part file. I am then adding drilled and tapped holes to it.

Every time I open the assembly with the part, the assembly opens the default C-Channel Structural steel shape and not the modified part file.

I can replace the shape with my modified file. But if I close the assembly and re-open, the assembly goes back to the default structural steel shape.

I didn't have any issues in 2010.

If you look at the attached images, one has the correct files listed. The other is what's shown after I save the file, close it, and re-open.