Disk First Aid:

Disk First Aid is a utility application that verifies the directory structure for any Mac OS Standard (HFS) or Mac OS Extended (HFS Plus) disk or volume. Mac OS Standard format is compatible with all versions of the Mac OS. Mac OS Extended is compatible only with Mac OS 8.1 or later. If you format a hard disk with Mac OS Extended format, you can't use that disk with computers that use Mac OS 8 or earlier.  To see how a disk or volume is formatted, click the icon of the disk or volume, then open the File menu and choose Get Info.

If the directory structure of a Mac OS Standard or Mac OS Extended volume is damaged, Disk First Aid can be used as a first step to repair the problem. If the damage is severe, other utility applications or repair methods may be needed.

Disk First Aid 8.5 corrects problems that may have occurred on Mac OS Extended format hard disks that were damaged by disk repair utilities incompatible with the new format. Some disk repair utilities may make inappropriate repairs that cause the hard disk icon to disappear from the desktop.

Using Disk First Aid:

Select the volume you would like to verify or repair. To verify or repair several volumes at once, hold down the Shift key and select each volume.

Click Verify to begin a verification process or Repair to verify and repair the selected volumes.

Write-protected volumes, such as CD-ROM discs and locked floppy disks, can be verified but not repaired. To repair other volumes, such as the startup disk, the volume where Disk First Aid is located, or a volume that has open files, Disk First Aid may need to quit all other applications, including the Finder. Disk First Aid will warn you if one of these conditions exists. If Disk First Aid has quit other applications, only the Finder will be reopened after you quit Disk First Aid.

To stop the verify or repair process once it has begun, click Stop.

The results of a verification or repair are shown in this window. To save the results in a file, open the File menu and choose Save Results.