Defragmentation & Optimization for Mac OS X


Every Mac user has noticed it; over time, your system slows down. This is particularly true in these days of constant security updates, as replacing operating system components not only increases file fragmentation, but also creates a more insidious problem—over time, the operating system itself ends up scattered all over your disk.

This, of course, doesn’t show up as fragmentation—after all, the files themselves are probably contiguous—but nevertheless, it takes your machine longer to start up, it takes programs longer to start, and it takes longer to get your work done.

iDefrag solves these problems and more, by defragmenting and optimizing your Mac’s filesystem.

New in iDefrag 2

Defragment Individual Files

Defragment individual files

Select and defragment individual files without touching the rest of your disk.

No bootable CD/DVD Required

No bootable CD/DVD required!

iDefrag no longer needs a bootable CD/DVD; instead, simply click Go and iDefrag reboots your machine into a special mode allowing you to defragment without using a separate boot disk.

Improved Performance

Improved performance

iDefrag 2 is the fastest version yet, including numerous performance tweaks to speed up defragmentation.

Improved UI

Improved user interface

For version 2, we’ve overhauled the user interface to reduce clutter and improved accessibility for disabled users.



Full support for Mac OS X 10.9 Mavericks

iDefrag is compatible with the latest versions of Mac OS X, and with the very latest hardware from Apple.

Time Machine

Works with Time Machine

iDefrag is safe to use on Time Machine back-up volumes if you so wish.


Native support for journaled filesystems

iDefrag knows about the journal and does the right thing automatically. No need to turn journaling off to defragment or optimize your disk.


Support for case-sensitive HFS+

Using case-sensitive HFS+ for compatibility with legacy UNIX software? No problem. iDefrag knows what to do.

Hot Zone

Supports the Hot Zone

Mac OS X is smart about the files you use the most. It moves them to an area on the disk called the Hot Zone, for improved access times. Unlike older defragmentation tools, iDefrag understands the Hot Zone, and knows which files should be there.

Thermal Monitoring

Thermal Monitoring *

iDefrag watches the temperature of your disk while defragmenting. If things are getting a little toasty, iDefrag will wait for the disk to cool down before continuing.

Powerful Algorithms

Four powerful defragmentation algorithms

Optimize or compact your disk as required. Includes a sophisticated programmable optimization engine—if you’re an advanced user, you can rearrange the contents of your disk how you want.


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.


Per-block and accurate whole-disk 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.


AppleScript and Automator support

iDefrag includes extensive AppleScript support and comes with an Automator action to help Automator users script defragmentation without needing to learn AppleScript.

*supported disks only



System Requirements

Mac OS X 10.6 or later (including OS X 10.9 Mavericks but not OS X 10.10 Yosemite, yet…), Intel microprocessor, 1GB RAM. Supports internal and external disks. To defragment your boot volume, you need to boot from a different volume (except for on-line defragmentation feature) or reboot into a special mode.

iDefrag can only defragment HFS and HFS+ volumes (i.e. Mac disks). It will not defragment FAT or NTFS volumes; if you are using these for compatibility with Windows systems, please use a Windows-based defragmenter.