The lost+found directory is located at the root of the file system. This directory is used by the fsck utility. The fsck utility is designed to check the file system.If the fsck utility in the course of inspection finds the data in the file system are damaged or do not have a name in the system (“orphaned”), then these files are placed in directory lost+found.
For example, if during recording a file on your hard disk, you suddenly turn off the computer (for example, to turn the power off), then fsck will then be able to find the file and put it in lost+found.
To view the contents of the lost+found directory, you must have linux mint root permissions.
You can use the following commands: