Can I make things worse by doing repairs with DiskWarrior, TechTool Pro, or similar disk repair utilities?

Unfortunately, yes. In most instances, these programs are good tools that help solve problems. But “repairing” certain problems can leave you worse off than before—in some cases, even destroy a disk from which a professional could easily have recovered data. Basically, when your drive’s directory is scrambled, anything that writes to the disk has the potential to do harm. Running TechTool Pro and some other utilities can actually write over the directory that it’s fixing, so occasionally it does damage.

Running a data recovery utility such as Data Rescue should be fine, if you copy the recovered files to a different drive. If you recover the files onto the same damaged drive, you will be overwriting other data you wish to recover, compounding existing directory damage and making things worse. A few utilities offers to save an “undo” file so that you can go backward, but we’ve seen them crash in the middle of a repair, and the Undo file itself was corrupted or incomplete.

You can also use DiskWarrior to recreate a disk directory, but don’t rush to write the new directory to the disk. Instead, click the Preview button on DiskWarrior’s last screen to mount the volume using the rebuilt directory and copy your files to another drive. Check the files thoroughly before you write the new directory or reformat the original drive.

If you are thoroughly backed up, you can use any repair utility with confidence. If you are not backed up and your data is essential to you, consider getting professional help. We’re not trying to scare you into always hiring us—we’re trying to scare you into always making lots of backups!

Published March 24, 2009 12:00 PM
Last modified on August 12, 2009 5:21 PM