Baking finished very quickly and not highlighted correctly

I am doing one of Unity’s official tutorials: Survival Shooter.

Unity version: 5.3.4f1
Device: Macbook, OSX 10.11

The problem: Baking process completes almost instantly and the floor is not highlighted (where highlight should mean that navmesh is calculated for there).

Here is the screenshot of it:

Then, I checked the completed scene (which was already created by Unity Team), it showed the floor fully highlighted. I just hit the bake again without touching anything and the same problem happened. So, there must be something else as I tried the original scene file without changing anything.

What am I missing here? Is there a Unity editor setting or something like that which can break the baking process?

For all those who had this problem: I found out that the “Environment” GameObject which supposed to have navigation-static children didn’t have all children marked as navigation-static. I fixed it by manually digging through children and marking “Floor” GameObject as navigation-static.