When I sometimes save my scene or project and then open it again everything deletes in the hierarchy and the prefabs ive saved can not be used in the sceen. This has happen many times.
Im not using any sharing systems and I dont think if reinstalling or uninstalling Uinty3D is the problem of my issue. Im using 4.3.3 
But i think when i have an error in the Console and when i then save the scene and then open it the issue arrive’s! Any options i can change or something like that?