Well, overnight I defragged two different Macs, one of which had over 20 million files eating up over 60 gigs on it. Worked perfectly. (Just FYI, the Mac doesn't really need defragging. That drive, in use for two years, had 20,104,190 files on it, of which 4213, or .02% (two one-hundredths of one percent) were fragmented. ) Under Panther, some defragging is built in, if you have journaling turned on....

TTP4 allows defragging (making sure the files are not split into different fragments), and optimizing (moving all the files next to each other, so the disk space is not fragmented). Optimizing places all the free space together, and so is useful if you're doing lare-file stuff, such as video or audio.

Anyway, IMHO, TTP4 is, at last, the great program it should be.