My map was running perfectly fine, and then I brought in two maps and meshes from two external sources. Not only are the meshes not staying loaded in the main level, but every time I try to play the level it crashes the entire computer to the point where I have to turn off the system. I tried removing the maps and meshes from the level and reducing the amount of other meshes in the map, but it still does it. Any ideas what the issue could be?