Universal Gamerz

I decided to look through my plugins, which I haven't used in probably a year, and I had about 8 plugins, including an ancient version of physics range extender, and I deleted them all, and it works now. I don't know why, but hey, it worked.

Lately I have been having the issue where a vessel or debris disappears whenever detached or switched, this applies to kerbals too, when I try to stage or fire a BD Armory missile, or try to EVA with a kerbal, it instantly deletes the thing that I am not actively using. I checked the debug console and it displays the error "Exception: MissingMethodException: Method Not Found: 'Part.FindModelComponents'. " My current mods are BD Armory, and DarkTexturePack. I also have module manager installed. I am currently running version 1.4.5.2243 if that helps. Any fixes?