sparklies on mesh

hi i have a mesh made in sketchup - I bring it into unity as a .fbx and unity seems to create a bunch of sparklies over the mesh when i generate a lightmap. I have tried imnporting the mesh to 3dsMax and welding the verts (that has no visible effect apart from increasing the number of verts!!!) I have tried splitting the mesh up differently too in 3dsmax, I have also tried getting rid of mip maps from the textures.

Any ideas???

It seems likely that your secondary UV map is Barycentric instead of being an atlas. This will cause overlap in the baked texture and make things sparkle. As a test you could create a simple cube using your workflow and test that in your scene.