Missing Asset(Dark Red/Brown in Editor)

Hi, I imported a model into my scene and it has been fine for the past week. It suddenly dissapeared today and there the font has become dark red/brown in the editor. If I click on the parent it shows the transform but the mesh is missing. All the children and brown as well. If I place a new one into the scene it displays fine. Does anyone know what is causing this. Thanks.

I am having the same problem and I am curious. Did you even get this fixed?