Rebuild Your Startup Disk
DiskWarrior now ships on a flash drive instead of DVD. If you plan to rebuild the directory on your startup (built-in) disk, you need to start up from another disk capable of starting up in OS X 10.5.8 through 10.13, such as the DiskWarrior Recovery flash drive or your Mac's OS X Recovery (the Recovery HD). OS X Recovery is available in OS X 10.7 (Lion) and later.
Whether started from the DiskWarrior Recovery flash drive, OS X Recovery or another disk, DiskWarrior can run from the flash drive to eliminate all damage to any HFS (Mac OS Standard) and HFS Plus (Mac OS Extended) disk directories, including your normal startup disk.
DiskWarrior can repair any Mac formatted disk including RAID volumes, Fusion disks, flash drives, and FileVaults.