Hello,

If this helps this is what it looks like when opened in SCE 2011+. The plate imports as a solid, there are some curves and there seem to be two holes in the outside wall of the ring. Once the holes are closed using the Repair Missing Faces command the item becomes a solid, but not a closed ring, it capped that micro gap internally with two faces to make sort of a ring with a micro split. There are inexact edges according to SCE, but I think that's a tolerance issue, nothing that is preventing the generation of the solids. What is interesting is that the file provided has the two internal faces of that sphere but not the outer ones.