hello Guys, i was rendering a small apartment today and i get that:
What is those shadows? I don know if its about my lightmass or the light that i use:
Help Guys 
Set Direct Illumination Occlusion in World Settings to default and turn of Use Ambient Occlusion, then try again.
Bsp resolution needs to be set to 2 for good results
Jacky is right
Didnt work…the shadows still crazy:
but seems that have less shadows, Christopher…where can i change the Bsp Resolution ?
I was trying to use the “Realistic Render Example” concept to make a nice realistic apartment.
You’ll need to adjust the lightmap resolution for each BSP mesh. This can be found in the details panel for the selected meshes.
Details Panel > Surface Properties > Lightmap resolution > The lower the value the higher the resolution (this is counter to what normal LM resolution settings would be with Static Meshes)