If you use spinning disks, you’ll have noticed that over time it takes longer and longer to access your files, to start your applications and even to start your machine.

This is an unavoidable consequence of the way hard disks work. It can be made better or worse by the design of the filesystem (and, actually, in this respect your Mac’s filesystem, HFS+, is one of the best), but in the long run there’s really no way to avoid this effect.

The cause of this slow-down is fragmentation, and when it happens, you need iDefrag.

Features:

iDefrag is not just a defragmenter
It’s a disk optimizer. That means it doesn’t just defragment individual files — it actually rearranges the files on your disk so that your system runs faster.

Works on Yosemite
iDefrag 5 works on Yosemite or later.
Older systems need iDefrag 2 instead. If you buy iDefrag 5, you will have access to older versions as required.

No CD/DVD or external disk required!
In most cases you will not need a bootable CD, DVD or another disk to use iDefrag.

Proper support for HFS+
iDefrag supports journaled and case-sensitive HFS+, and knows about features like the Hot Zone.

Defragment while the disk is in use
iDefrag can perform simple defragmentation while the disk is still in use. Good for situations where you don’t need the full power of the optimizer, but have a few fragmented files you want to sort out.

Beautiful, accurate display
See the individual blocks used by your files, watch iDefrag move them around in real time, and get an at-a-glance overview of the state of your disk.

License: iDefrag 5 is a paid upgrade from previous versions.

Requirements:
OS X 10.12+
64-bit Intel