Unity 4.5 Colliders not colliding

Unity Engine
1

Updated to Unity 4.5 and all of a sudden colliders with rigidbodies are passing through each other. They are not colliding.

For example If I place a plane with a box collider.

Then place a cube somewhat a distance over it with a box collider and rigidbody.

Then when I play it, cube falls through the plane. It should stay on the plane because the colliders collide and its the normal behaviour but its not happening.

Is it a bug on Unity 4.5?

2

The problem was in the project I was working on. Fixed it by going to Edit->Project Settings->Physics