Hey I've been having this problem. I have a mac and have been trying to make a mod pack for my youtube! I've been having trouble when ever I install forestry, thermal expansion, or rail craft it doesn't crash but it freezes then goes black! I have to force quit it and then open eye doesn't work and I can't tell whats wrong. Also they are mods I've seen together but always seam to crash when I try and make a pack! Please help. The mods I have so far that don't crash or I've fixed the crashing (to be clear not freezing but crashing):
Botania, Buildcraft, Chisel, Code Chicken Core, Extra Tic, Forbidden Magic, All of growthcraft, Iguana tweaks, tinkers construct/mantle, iron chests, journey map, natura, nei, nei addons, open eye, optifine, thaumcraft, thaumic tinker, waila.