The Apple site gave the following instruction for using an external hard drive - "To copy files to it, just drag and drop any file, folder, or application onto the volume icon. If you double-click the volume to open it, you can add folders (press Command-Shift-N) to help organize your content." The problem is, copying files is not saving space on the internal hd, how do I move the files rather than copy them? The files are mainly music in iTunes and photos in iPhoto. Any help offered will be appreciated as being new to Mac does have it's problems after years of and ongoing use of PC's.