iDefrag free download for Mac


10 July 2019

Disk defragmentation and optimization tool.


iDefrag helps defragment and optimize your disk for improved performance.

iDefrag Features
  • Supports HFS and HFS+ (Mac OS Extended).
  • Supports case sensitive and journaled filesystems.
  • Supports adaptive hot file clustering ("Hot Zone").
  • Four powerful defragmentation algorithms:
    • Compact data, moving all free space to one place.
    • Optimize filesystem metadata.
    • On-line defragmentation.
    • Defragment whilst your disk is mounted.
    • Advanced programmable optimization.
    • Rearrange your disk the way you want.
  • B-Tree metadata file compaction/optimization support.
  • High-performance user-defined file classification engine.
  • Per-block and accurate whole disk display.
  • Detailed statistics so you know whether you need to optimize.
  • Inspector allows you to view details of individual extents/files.
  • Quickly jump to specific files to examine them in more detail.
  • Altivec accelerated display for improved performance.
  • Auto-update feature ensures you always have the latest version.
  • Fine-grained security, just like iPartition.
  • AppleScript support.

Note: Coriolis Systems Limited is shut down and does not provide any support for its products. The license information can be obtained from the Coriolis Systems' website

What's new in iDefrag

Version 5.3.1:
  • Release notes were unavailable when this listing was updated.

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282 iDefrag Reviews

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Rate this app:

24 December 2009

Most helpful

The demo only works on 100MB and smaller drives?? So anyone, like me, who doesn't still have a drive left over from 1997 is basically screwed. That makes this demo useless to me. Coincidentally, it also means it doesn't get purchased.
Like (13)
Version 1.7.2
03 January 2020
so i would rate your app cause i am a beta tester ,but the problem is i never got to try it it downloaded fine but when it was opened i recived a msg that it was damaged and to toss it out so thats what i did .something you should look into .let me know when you have fixedit and i will give it another shot
Version 5.3.1
09 July 2019
A huge "Thank You" to the developer! I wish you all the best for the future. Both applications, iDefrag and iPartition, are outstanding.
Like (1)
Version 5.3.1
09 July 2019
I did benefit from this nifty utility for many years and now it’s gone for good. At least the developer has been generous enough to offer it for free to those who still use the older Systems. Just go to their site to pick up your free license. Fariborz AMIRSHAHI - Verona (Italy)
Like (5)
Version 5.3.1
2 answer(s)
09 July 2019
He might as well, seems to have little to loose at this point.
09 July 2019
I don't know, but when a developer like this retreats from the market, it's a great defeat for the Mac community.
Like (1)
11 May 2019
Free?? Why is it asking me do drop my license when I try to install it?
Version 5.3.0
1 answer(s)
09 July 2019
The license information can be obtained from the Coriolis Systems website
Like (4)
22 April 2018
From the Coriolis website: "Support for this product has ended. iDefrag works fine on macOS 10.12 and earlier, but has some problems on macOS 10.13 (High Sierra). There will be no further updates or bug fixes; the product will remain available for download and purchase for the benefit of users running earlier versions of the macOS."
Like (2)
Version 5.3.0
22 January 2018
Hi MU community! I hope someone might be able to advise me here.

I recently upgraded my OS from 10.7 to 10.9.5, and I already had iDefrag 1.7.3 (229), which I'm using now.

As we speak, I'm about 14+ hours into a iDefrag Optimize on a 4TB external drive that only has 650GB used, and the Location Indicator is only about halfway through the populated area of the Whole Disk Display.
I'm wondering: Does this mean I have another 14+ hours left to wait for this, and if so, is this normal/OK for iDefrag to take some 14-28 hours to optimize 650GB on a 4TB drive?!

Here's my setup:

Version: 1.7.3 (229)
Algorithm: Optimize
Class Set: Default
Enable per-class sorting: SELECTED/CHECKED
Skip files that cannot be defragmented due to lack of free space: SELECTED/CHECKED

Model: Late-2011 MacBook Pro
Processor: 2.5GHz Intel Core i7
Memory: 8 GB 1333 MHz DDR3
OS: 10.9.5 (13F1911)
Startup Drive: 1.05 TB SSD SATA
Connection: MacBook Pro ThunderBolt 1 <--> Elgato ThunderBolt 2

External drive being defragged/optimized
Brand: Seagate
Model: Expansion Portable HDD (STEA4000400)
Size: 4TB
Connection: Seagate's USB 3 <--> Elgato USB 3

Brand: Elgato
Model: ThunderBolt 2 Dock

ALSO - Regarding upgrading from iDefrag 1.7.3 to 2.2.8 (per Corialis website suggestion for OS10.9.5):
a. What's the process?
b. What's the cost?
c. How would it benefit me (if at all)?

I look forward to some help, as my work is halted until I finish defragging some drives, and I'm wondering if I need to budget 28 hours of computer downtime per 650GB of hard drive defragging :-|

Version 5.3.0
06 December 2017
Anybody have any benchmarks that show an improvement in drive performance after defragging, as advertised?
Version 5.3.0
1 answer(s)
17 April 2018
Yes I do and WOW... I was getting about 90MB/s read and write before in an 8TB drive that is 95% full, and just after 4 hours of defragging (out of what looks like will take days) it is now back up to 170MB/s. Very impressive and surprising! Can't believe I told people "Macs don't need defragging" for so many years!
11 August 2017
I haven't tried the software but just wanted to point out that 'defragging' a modern SSD hard drive will have no benefits and will actually decrease the life of your SSD. See for more info.
Like (1)
Version 5.2.1
13 May 2017
While it is used the version recommended according to S.O works perfectly. If you install the 5.1.4 (or superior) in Yosemite or El Capitan, can damage the disc, so that there is to reformat and to reinstate everything.The system of updates of the program, must have had this in account.The last compatible version with Yosemite and Capitan is 5.1.3 and now it does not try to update to a later one, as it must be.It is a good program, and it helps enough to maintain discs in sequence. But from time to time, the updates are not without risk. Due to him, I have had problems several times, the last ones with the passage to Yosemite,and it makes a pair of months with these incorrect updates of iDefrag.In addition, it is possible that some problems that I did not know to identify also came to use one more an up-to-date version of the indicated thing.
Version 5.1.8
1 answer(s)
Coriolis Systems Limited
Coriolis Systems Limited
22 May 2017
None of the recent updates will "damage the disk, so that there is to reformat and to reinstate everything". That is not true and not necessary, no matter which version you use, and it's very unhelpful suggesting that it might be, because it causes people who have trivial problems to go reinstalling their machine when they see comments like this.

In particular, IF you have a problem booting into restart-and-defragment mode (which is a problem that is still affecting a handful of users and which we're investigating), the thing to do is to restart the machine *and wait*; it should boot normally, though it might take a little longer than usual. In the unlikely event that it doesn't, PLEASE GET IN TOUCH rather than jumping to the conclusion that you need to reinstall from scratch.
Like (3)
25 April 2017
It is very easy to use. Very useful to install it on old Mac hard drive and get more free disk space.
Like (1)
Version 5.1.8
1 answer(s)
26 April 2017
Like (1)