If you open your Mac’s boot drive, you may find a folder called “lost+found” next to the System, Applications, Users, and other system directories at the top level of the drive. If not, then this folder may still be present, but could just be hidden, so check for its presence by pressing Shift-Command-G in the Finder, and then entering “/lost+found” (minus the quotes) in the drop-down panel. If this reveals the folder, you may find a number of files in it that begin with the name “iNode” and end with a series of numbers.
If you cannot locate this folder on your drive, then everything is well with your system; however, if the folder is present and has these files in it, then you may be experiencing hard drive problems. For one, these files may take up significant space on your hard drive, but also indicate mishandling of your filesystem structure.
Since these files are just archives, you can read their contents using basic Terminal commands:
- Open the OS X Terminal
- Run the following command to list the specified archive file’s contents (replace ####### with the numbers in the archive’s name):
xar -tf /lost+found/iNode#######
- Press Enter to view the file’s contents.
At this point, you may see a massive number of files listed, but should be able to scroll up and determine what the content of the files is. If needed, you can extract the archive by running the following command:
xar -xf /lost+found/iNode#######
After your cursor is dropped back to the command prompt, you can go to the lost+found folder (as described previously) and then drag the extracted archive’s contents to more relevant locations on your drive, and make use of them as you will.
If you find you do not need the files’ contents, then you can safely remove the file, or the entire lost+found folder. If future filesystem checks find problems, then the folder will reappear and you can similarly check it out.
Generally, the lost+found folder on your drive will appear if filesystem inconsistencies are found, which may happen when the system boots after a power failure, hard shutoff, or similar reset. After such events, the system is expected to manage inconsistent files, but if the lost+found folder keeps reappearing and you see multiple files showing up in it, then you are very likely experiencing a filesystem problem that will require you immediately back up your drive, format it, and restore OS X. In general, such problems cannot be fixed by simply running a filesystem check or repair, and the more interaction you do to your drive, the more chances you have for the damage to affect the files on it.