I took a GIS class a while back and am coming back to working with Arcmap. I don't why I can add some shapefiles and not others. All the other files are located in the general zip file as well (SHX, SBN, SBX, etc.). When I try to add some file it'll say error opening feature class and for a few it will also say could not add the specified data object to the map. I figured maybe there are not enough features so maybe I'll try to convert it from a feature class to a raster? I've had to uninstall the program once because somehow the data source for some my shapefiles were missing (?), thus it was not showing up. Problem fixed on that front but now I have to get these shapefiles for my map. I'm trying to add HUC-12 data from the geospatial gateway showing sub watersheds.