yeah, the polycount is the reason the mesh is not importing.
But there's something crazy going on with your mesh lol
2 earrings
each earring is made of 4 separate objects (identical, overlapping)
each of these objects is made of 16 connected objects (also identical and overlapping)
So you have 128 earrings which is why the mesh has 122k tris lol
Needless to say, whatever you did to get there, don't do it again. It could have been Shift D to duplicate or maybe even Array modifier.
To fix it, in Edit mode select everything with A and Remove doubles with Merge distance set to 0,0001.
There are other issues you need to fix because the mesh will not work as intended:
To move properly, the earring must be assigned to the head bone. Right now they are assign to Group which is not present in the rig. So you need to double-click on Group and paste b__Head__ instead.
The uv map must be named uv_0. There should be a second map responsible for morphing called uv_1, otherwise it will morph randomly. You can transfer this map from maxis earrings.
- in s4s clone any maxis earrings, export the blend;
- in your scene in blender go to File - Append, find the exported blend file, choose Object, then choose s4studio_mesh_0, Append from Library;
- you can delete rig.001 and bone_bone_shape;
- select your earrings, create a new uv map, rename it to uv_1;
- add Data transfer modifier, choose s4studio_mesh_0 as Source object, set the rest like in the pic, hit Apply;
The earrings must be vertex painted with 007f00
That's also not how you'd want to unwrap the mesh for uv_0 - and that step should be done before you duplicate and mirror the other earring - but for the sake of learning it will do.