I received an assembly that was saved as a STEP file. When I open it and save it as a SW Assembly, the elements in the feature manager look like in the picture. Eventhough it's an assembly, I can't float any of the elements or apply mates to them. Any thoughts on what I could do?
that is the new 3D interconnect functionality.
you can either turn it off in settings before importing the step file or with it open as you show, right click at the top of the tree and choose dissolve - this will break the link to the step file.