FAQ: Why is a shapefile's icon a green question mark in ArcCatalog?
Why is a shapefile's icon a green question mark in ArcCatalog?
ArcCatalog does not recognize the file as a valid shapefile. In order for a shapefile to be valid, it must have at least these three component files: shp, shx, and dbf. One of these three files is missing. Replace the missing file.