In the window that opens there will be a line 'File System'. If the format is blank, click on the Info button at the top of Disk Utility. However, if the drive reads as PC Exchange, ExFAT, FAT16 or FAT32, NTFS (and more) then the disk is PC formatted and you will need to recover your data using a Windows-based utility while the drive is connected under a Windows operating system.

If the drive meets the formatting requirements listed above, DiskWarrior will work to rebuild the directory of the drive. At the bottom of the screen you should see the line 'Format'. Instead you may see 'untitled' or 'disk1s2' (your specific numbers will vary). This may not be the recognizable name of your drive. The second line should be indented and have a volume name. The first line should state the manufacturer of the drive (LaCie/G-Drive/etc) and the size in gigabytes (GB) or terabytes (TB). Your drive should appear with two lines of data: To double-check that the directory of the hard drive is readable by DiskWarrior in its current state, please open the Apple Disk Utility (located in any computer's Utilities folder or on the Apple Install CD/DVD under the Utilities menu or via the Recovery HD in Mac OS X 10.7.x Lion and later).

Did you reformat this drive when you first used it or did you use the drive as is?

Macs can read from and write to a variety of disk formats and many external disks come PC formatted from the factory. DiskWarrior 5 will attempt to rebuild the directory of a hard drive as long as it is formatted using the format of Mac OS Standard, Mac OS Extended, Mac OS Extended (Journaled) or Mac OS Extended (case-sensitive).

Rebuild trash on mac external drives