I had the same issue. The actual shapefile (.shp) requires the companion files: .dbf, .shx, .prj etc..so make sure you have all of those. From elsewhere on the web: “It is critical that all the files belonging to a shapefile are treated as a single unit. If the shapefile is edited at any stage, even just attribute changes, the FIDs (feature identifiers) change, which means the order in the .DBF file is changed.. should you edit a shapefiles’ attributes and only copy the .DBF file, overwriting an existing .DBF file the shapes will point to the wrong rows. Always copy ALL the files together.”