I have a 27" 3.4 Ghz iMac 12,2. My desktop shows Macintosh HD and Macintosh HD 2. When I double click the icon for Macintosh HD the window that comes up shows my files on Macintosh HD and Macintosh HD 2 as being virtually empty. I keep getting notifications from my Checkmate app that I have less than 5% space left. How do I, or maybe I should say can, I save to the HD 2?