Yeah, ATM's a little buggy. It ruins Astronomer's Visual Pack and may also wreak havoc with your parts. That said, OpenGL mode isn't a safe alternative either. Whenever I try and run in OpenGL my game crashes with a memory error, supposedly pointing to illegal memory access. If you're going to use CMES, it's best to either a) go Bob Fitch Style and don't install parts you don't need or create a separate install with CMES and nothing else to minimize memory use. Either works, I use mostly a) with a bit of .