Alsoft’s DiskWarrior doesn’t offer the broad range of hardware diagnostics that TechTool does, nor does it offer the array features for things such as formatting, resizing partitions, and defragmenting drives that Drive Studio offers. It is designed as a drive repair tool and it can generally be considered the most powerful such tool. DiskWarrior can rebuild disk directory structures better than most tools; if it cannot repair a disk, it can usually build a replacement directory by examining the files on it. In fact, DiskWarrior is so often successful that many technicians respond in shock or surprise when DiskWarrior cannot repair a disk. In the process of rebuilding a disk’s directory, DiskWarrior also optimizes the layout of directory data for improved performance, particularly for tools such as Spotlight and the Finder, which rely heavily on disk directory information (DiskWarrior optimizes only the directory data and does not optimize or defragment the file data on the disk).
In its most recent version, DiskWarrior also offers the ability to verify and repair Mac OS X permissions as well as the ability to check for and repair damage to various types of files on a Mac OS X startup drive. It can verify and repair preference files, symlinks, and folder and file length limits—all of which can become corrupted and cause serious issues under Mac OS X. It also supports based tests of a drive’s hardware using SMART technology.
Although it doesn’t provide many bells and whistles, DiskWarrior is often the last-resort tool for problem drives and it more often than not can repair them successfully. It also has a very clean and easy-to-use interface that includes very good explanations of each feature and step in a repair process. When rebuilding a disk’s directory, it also offers the option to preview the replacement directory to ensure that it resolves problems and to copy data from a drive experiencing physical failures. If you are looking solely for a tool for resolving hard drive problems and checking for certain types of file corruption, DiskWarrior is an excellent choice.