This is one of my most valuable software items on my hard disk.

In answer to the various comments about speed, I must say that iDefrag is perfectly comparable to Norton Speed Disk, which I've used on every system since System 6.0.7.1 on my PowerBook 170. I don't think it's either faster or slower, as long as you have a recent model computer with a reasonable clock speed and hard disk.

I really feel that this is safer and more stable than Norton Speed Disk. I lost the entire contents of my hard disk repeatedly through the years due to the various faulty Norton Utilities that always lacked minimal safety mechanisms built-in. In all, it definitely did far more harm than good, but I'm addicted to utility software, so it's hard for me to not run whatever I have and to own all that is available. I must be obsessive-compulsive, or something.

I was frustrated that DiskWarrior was not updated after somewhere around OS 10.2, and it only rebuilt the directory and not the actual files on the hard disk. iDefrag does both with the same level of safety as Disk Warrior did.

Any optimization software will take a couple of days to complete during the first run, depending on the amount of data that you have, but this software is configurable to make it shorter if time is a greater priority than perfectly compact and ordered data content.