After attempting most of the procedures above I finally found a solution that worked for me. It may or may not work for you as it may have been an accident that I found this and may be perculier to my setup. Under "My Computer" my Ermatic tablet appears as 2 drives, The "ES" tablet and a second SD drive (drive letter will depend on the number of drives in your system). When putting files on the external SD drive under the "ES" external SD, the file explorer app does not see them. It reports an empty or no folder. Consequently, putting the files into the second drive works very well as all files are then recognized. This is similar to my first tablet which was a NOOK.