Layers, Prefabs and Build Settings have been deleted

I am making my game in unity 5.01 and accidentialy opend it ip in 5.00f4. It gave me some kind of error message about layout or somthing like that so I realized I had opend the wrong unity and reopend it in unity 5.01 but for some reason all of my prefabs are blank, the build settings are empty and the layers i made are blank so when i select an object that used to have a layer instead of saying default in the layer slot it is just blank. I think everything else is working but is there a way to recover what I lost or will I have to do it all again?

When you get this type of problem not is always possible to recovery.

  1. Try to clean up automatic generated files (like files/folders defined here gitignore/Unity.gitignore at main · github/gitignore · GitHub). Reopen and fix any compiler bug.

  2. Create a new project, copy your scripts, check if it is ok, copy your raw assets, confirm, copy your prefabs. If you don’t have checked “Visible Meta Files” (http://docs.unity3d.com/Manual/ExternalVersionControlSystemSupport.html) there is little change that this solve.

  3. If you have all assets serialization mode to text (Unity - Manual: Editor you can try to identify your problem manually and fix your self. It is hard but possible.

In the end, the best that you can get is a lesson. Always backup your work, specially when working with tools. Learn how to use a version control, or at least, a script to automatically backup like hourly.