Found an external USB drive and plugged it into a 4-year-old Mac Mini. Works perfectly. I am the problem because I do not know the key strokes to make it work. Have been able to figure out Eject and have opened an Excel file by trial and error. I knew there was data, but had no way to know the program that wrote it. And have no clue about pictures. My only image app is Bridge and Photoshop. Anybody know which buttons to push?