Maintenance of Mac OS X is different than previous Mac operating system versions, and it has been found that some utilities may cause more harm than good if used indiscriminately. Using the wrong version of a utility to correspond with your operating system can yield undesirable results. In addition some symptoms of system issues may be only addressed by replacing hardware that may look identical to those which some of these utilities fix. A damaged directory may look identical to a dying hard drive. Using a scan of a dying hard drive may speed its death, so backup is the most desirable maintenance you can do to any system. There are utilities which can copy an entire hard disk, though if you can't afford those, there are these instructions on backing up important 10.4 files:
For other applications feel free to ask here in Discussions for suggestions for your particular needs. If your drive is already inaccessible due to some failure, and you aren't backed up, sometimes the inaccessibility can be due to user folder being named or moved as this article suggests:
If that is not the cause, then the first thing I'd when not backed up is use Prosoft Data Rescue and an external hard drive to recover your information:
Once you are sure you are backed up at least twice, here are the known utilities compatibility listing by operating system, as feedback for this tip, please provide any additional known compatible utilities by operating system so that they may be added:
Mac OS X 10.4 through 10.4.4: Alsoft Disk Warrior 3.0.3, Micromat Techtool Pro 4.0.4, Techtool Deluxe 3.0.4 (provided as part of AppleCare CD).
10.3.3 through 10.3.9: Techtool Pro 4.0.3
10.2.1 through 10.3.9: Disk Warior 3.0.2
10.2 through 10.3.2: Techtool Pro 4.0.2
10.1 through 10.3.9: Techtool Deluxe 3.0.3
10.0 through 10.1.5: Techtool Pro 4.0.1
Mac OS 9.0 through 9.2.2: Disk Warrior 2.1.1
8.6: Disk Warrior 2.0.5
System 7.5.5 to Mac OS 9.2.2: Techtool Pro 3.0.9
Sources for compatibility information
Not all of the applications above have been tested by the author of this tip, and we are relying on the third party for compatibility information. As long as you are backed up, these utilities will simply supplement your backup, and speed your recovery over recovery from backup if you are already backed up if they end up repairing the drive. Otherwise when they don't work recovery from backup to a new drive should always be considered an available option.