Directional light shadow not displaying

When I use Unity 4.3 ,the real time shadow works fine on mobile device and PC Editor (OpenGL ES2.0 Simulation).

But real time shadow not working when I use Unity 4.5 and Unity 4.6 that the same condition used in Unity 4.3.

Here is my testing procedure.

  1. Create 3D Objects - Plane (Receive Shadow)
  2. Create 3D Objects - Cube (Cast Shadow)
  3. Create Directional Light ( Enable Hard Shadow)
  4. Real time Shadow works fine in Unity 4.3 but now working on Unity 4.5 and 4.6(PC Editor OpenGL ES2.0 Simulation)

Does anyone have the same problem ?
Or the solution? Thanks very much!

Dunno if it has anything to do with this, but some shaders won’t work with real time shadows if they are lightmapped.