MicroMat’s TechTool Pro is probably the most comprehensive hardware testing and diagnostic tool outside of the tools Apple ships to authorized repair centers. It can test virtually every internal component of any Mac model. This is a great diagnostic tool for determining whether a problem is hardware-related and, if so, which piece of hardware is the cause of that problem. It can also verify the integrity of a hard drive’s directory structures as well as the integrity of the files stored on a hard drive and can be used to repair corrupted structures and files.
Like Drive Genius, TechTool Pro offers the ability to defragment and optimize the contents of a hard drive and to securely delete data (you can choose to securely erase an entire drive, free space, or specific files and folders). TechTool Pro also enables you to configure automatic testing of a given disk’s directory structures as well as to regularly query SMART status of hard drives, which can alert you to problems before they become drive failures. It also includes some data-recovery capabilities.
One of the most interesting features of recent releases of TechTool Pro is its eDrive function. eDrive creates a small emergency partition on your hard drive that can be used to boot a computer should the primary start partition fail due to corruption (in the event of a physical drive failure, this partition will not work any more than the main partition on the drive). The emergency partition includes files needed to boot the computer and a copy of TechTool Pro. This can be helpful in situations in which you do not have access to the bootable TechTool Pro DVD.
TechTool Pro is actually available in a variety of forms. In addition to the commercial TechTool Pro package, a version called TechTool Deluxe is included with AppleCare Protection Plans). MicroMat also includes a version on a small bootable Firewire flash drive called TechTool Protégé that is extremely portable and a version called TechTool Protogo that can be installed on an iPod, turning it into a portable and bootable diagnostic drive.
TechTool Pro is a very good all-round diagnostic tool. It is particularly helpful for support professionals because of its capability to test hardware. However, in my experience, its hard drive repair and data recovery features, while being more successful than Disk Utility when working with corrupted hard drives, tend to fall short of the capabilities in other tools—including Data Rescue II, Drive Genius, and Disk Warrior.