Well, Im here 7 years later and it must be a little late, but lets write it down for those who will google this issue. In my case, dots were produced by some very rare and unreparable bug in 3dmax rasterization pipeline, and I fixed it by 1) reseting 3dmax (File-> Reset ) 2) merging all the geometry from problematic file…
I haven't tried to bake a normal map in 3dmax, but I think I will because of the lack of detail mudbox makes in the map I dont see a thing of my normal map in 3dmax when I apply the normal map to the mesh (I think it's just my fault that I'm doing something wrong)... any way progress on the mud,.. -GuranGa