"DiskWarrior is the safest, most technologically advanced, most
powerful utility to eliminate directory damage available for any
computer."

New features in version 4.0:
* Universal binary
DiskWarrior 4 works on both PowerPC and Intel Macs.

* Significantly faster
For many disks, directory rebuilding is twice as fast as the previous version.

* Repairs invalid file permissions
No need to run more than one utility. Repairing permissions and
repairing directory errors are the two most common disk maintenance
procedures.

* Includes an additional suite of file and folder tests
Finds problems before they cause you trouble.

* Identifies corrupted preference (.plist) files
A bad preference file can wreak havoc. Now you don't need to reset
all your preferences because a single preference file is bad.

* Recovers more data from drives with hardware malfunctions
Recover your important files from most failing drives, possibly
saving you thousands of dollars in professional recovery costs.

* Detects and repairs more disk problems than ever
The best is even better.

* Repairs and rebuilds FileVaults
FileVaults suffer from directory damage too. DiskWarrior is your only
choice if you need the data security of a FileVault.

* Repairs and rebuilds disk images
Get back the files you thought you had safely tucked away in a disk image.

* Fully supports case-sensitive file names
If you use case-sensitive disks then DiskWarrior is your best choice.

* Repairs and rebuilds Attribute B-trees
First introduced in Mac OS X 10.4 (Tiger), Attribute B-trees are a
new addition to the disk directory. DiskWarrior rebuilds them as
easily as it rebuilds the original catalog and extents B-trees.

* Repairs Access Control Lists (ACLs)
ACLs are a new permissions model first supported in Mac OS X 10.4.
DiskWarrior repairs them too.

For more information please visit the DiskWarrior 4 page:
http://www.alsoft.com/DiskWarrior/index.html