Why do meshes keep going missing?

A lot of my models have suddenly lost their meshes.

Missing (Mesh)

The last thing I did was reorganised the assets folder from within Unity. I saved it and opened it again later to find most meshes missing.

Any advice on how to get them back without redoing the entire scene?

Running Unity 3.4.1f5 (Windows 32bit)

Figured out the problem. My fault!

I’m deleting the prefabs the objects originally came from. After a prefab connection is lost due to modification by an instance on the scene I didn’t think deleting the prefab would affect it. It does.

Summary: don’t edit models in Unity and then delete the prefabs it came from.