I'm getting "format != kRTFormatARGB32" error when enabling shadows.

I'm getting this error whenever I'm enabling shadows in my scene, but everything seems to work normally:

format != kRTFormatARGB32
UnityEditor.EditorGUIUtility:RenderGameViewCameras(Rect, Rect, Boolean, Boolean)

I have nothing special in my scene (FPC, Terrain, Cube and Directional Light) and I'm using Unity 2.6 on my old Macbook. I can provide more details of my system if it has anything to do with this error.

Does anybody knows how to solve this error or why I'm getting it?

I'm pretty sure an Intel GMA 950 won't support render targets, which is what Unity uses to render shadows. However I would have thought Unity would handle the error and given something a little more concrete in it's feedback. Enabling shadows on a system with that GPU (and I use the term loosely) will be incredibly taxing if you do get them to work.