Unity wiping scene

I fill a scene with carefully placed prefabs, lights, and cameras. If I open a new scene I lose all my placement and my hierarchy is empty except for a camera. Unity restores it to the default scene. I get the same result on start-up. This will occur after saving the scene. What am I missing?

I am running Windows 7 with unity 3.4.

Thank you

The all point of a new scene is for it to be new. Brand new, nothing, nada. Except for the camera.

If you want two scenes with just a little differences, you should duplicate the one with everything setup correctly and edit that duplicate.

Wow I’d really like an answear for this. I started the debugger, it told me unity was already running, I saved and closed unity. Started the debugger again and all my objects in my scene were gone. In fact, all the objects in all my scenes on all my projects are gone (even the tutorial).

I re-installed unity and now it works fine. Not much of an answer but it worked.