Boolean Intersect - Cannot execute boolean operation This is my first project using Blender, so it could just be a rookie error.

I'm trying to extract a specific part of a city model using Boolean Intersect, with a cuboid, however I keep getting the same error of "Cannot execute boolean operation".

Unfortunately I'm unable to share the Blend file as it contains the model.
Try this:

1) In edit mode select all and remove doubles (W -> remove doubles ) when recalculate normals (Ctrl+N )

2) If it doesn't help, try newer version of Blender. It has a new Boolean solver "B-mesh" that can work with more complex geometry. 

3) Check your model with 3D-printing toolbox add-on: Checks -> Solid must output 0 manifold edges.



If it's not so, you can select all bad edges by pressing button here in edit mode: