I recently had to replace the internal hard drive of my MacBoo Pro (13-inch, late 2011). In attempting to free up some space, I have run across a "lost+found" folder that contains two iNode files of about 3.5 Gb each. If I look at the disk image using Disk Utility, it appears the files are OS X installers. Can I safely delete these files? Do I need both of them, they are dated just over a year apart?