Using TechTool Pro with Mac OS X: MicroMat speaks

Although TechTool Pro 3.0.3 contains no code that deals with the inodes that UNIX uses in its disk directory, it is safe to boot under Mac OS 9.x and rebuild the Catalog B-Tree and Extents B-Tree using the Directory Maintenance feature of TechTool Pro.

Do not attempt to use TechTool Pro 3.0.3 in the Classic environment.

We recommend that you not use the disk optimizer in TechTool Pro to optimize Mac OS X volumes. The long filenames (stored in Unicode) may cause the optimizer to fail to complete its task. There is no risk to the data, because the optimizer stops as safely as it would if you clicked the Cancel button.