Are you sure everything is there? In textures, materials, and if everything is right? If yes, then try running as admin, and/or switching the rendering system. Computers can have viruses too. Make sure you don't have a lot of stuff on your FeralHeart, like downloaded stuff, MODs like a new interface, mostly downloaded stuff, and if you have a lot, then I'd suggest deleting some, like downloaded maps, too.
Check to see if your computer has a virus if nothing helps, I'd suggest. Might not help, but try my first suggestion first, which may be okay, also, this is very important: Check your particle folder for duplicates or whatever they are called, example: bonfire_01.particle you know, an extra particle thing like that. That might be causing it if you see one.
Delete it if you see one. Hope any of these helps~
~Hugrf
