Rukey

Hello, I'm pretty new to this program but I thought I'd give it a go anyway because I've heard alot of good things. I have a mesh which has been sculpted in ZBrush, I have decimated it from it's 16million original poly count to just over 100,000 (99.3% reduction in count). I can open the .obj prefectly in 3DS Max and equivalent but as soon as I import my mesh into 3D Coat the mesh looks like it's been completed reduced and has holes in certain places. Is it a case of 100,000 polys being too much for the program to handle? or am I doing something wrong?