Above is the link to the FTP site provided by SCDNR. It is free data provided by the State of South Carolina. I downloaded the Horrydem and attempted to import it into QGIS but I continue to get the
invalid data source error message.
All of the files should be the same. If you're able to import it into QGIS, please let me know how you did it. I've attempted both the vector import command and "drag and drop" as I've seen others mention. None have worked.