Just wanted to post my experience getting the 64bit Unity Player working with KSP. Simply followed the first post instructions (although I replaced the entire Mono folder with the one from the 64bit Unity Player and updated UnityEngine.dll as well), started the game with all of the mods I use installed (Interstellar, KAS, NovaPunch, Firespitter, KW, EnvironmentalVisualEnhancements, Kethane and many others - can get a full list with versions if it ends up being needed for any reason). First launch of the game crashed as soon as it tried to go to the title screen. Checked the crash log and the stack trace was referencing Kethane (small snippet): (0x0000000083A1E0AD) (Mono JIT code): (filename not available): Kethane.EnumerableExtensions/<AdjacentPairs>d__0`1<Kethane.Cell>:MoveNext () + 0x1ad (0000000083A1DF00 0000000083A1E13A) [0000000004F04D48 - Unity Root Domain] + 0x0 Axe-murdered Kethane... runs beautifully with Environmental Visual Enhancements, Clouds (not sure about City Lights, removed them from my install). Conversely, Kethane seems to work just fine if EVE is removed. Lilleman - You are a scholar and a gentle(insert appropriate gender-specific term). Spectacular work!