Tamb0, I am running on a I5cpu 750 2.67 GHz / 4 GB mem. / 64 bit / ATI Radeon 4800, so I do not think this the point. I think there is something wrong with the editor??(bug), between modding I was testing differend areas, and suddenly the bug appears. The house-mod started in markarth, with a connection to the warrens, and a large cave connected to the house, the cave connects to several dwarven cities and other rooms. There is also a connection from the house to the markarth catacombs ( in development), like I said, I can walk trough all the levels, except go outside. So there are a few dungeons attached, and I spend a lot of time on it, placing items, navmeshing and so on, but now I am stuck and still not finished. Is this the solution for the problem, or must everybody who wants to play the mod edit his skyrim.ini. file??? Regards, Veteron