I am on Mavericks now but before I switched, I installed OS 9.5 on a USB stick to see how I like it. After this try-out installation (and the MP still on OS 8.5) I discovered that when starting up with option pressed, I see my usual start-up disks but ALSO a "OS X Base System" that is obviously a left-over from my earlier Mavericks installation trial. Now on Mavericks I could see this disk image even in Disk Utility when on the recovery partition. There it appeared as "disk6" disk image containing 1.25 GB. I searched for this disk image in the invisible files, but didn't find it. I want to erase this left-over stuff as it takes space and does who-knows-what. How can I erase this thing? Thanks.