Coriolis Systems was founded by Alastair Houghton back in 2004, who had left his job around a year earlier to write the company's first product, iPartition, after becoming annoyed that he couldn't repartition his new laptop to install developer versions of Mac OS X without wiping it clean.

He went on to develop iDefrag, in part to work around a limitation of the original version of iPartition, then hired Chris Suter, who was responsible for adding a number of features to the products (most notably, NTFS support, reboot-and-defragment mode in iDefrag and a new data movement algorithm for iPartition that was more efficient and enabled the unique recoverability feature in that product).

Alastair hired James Snook, and subsequently Ed Warrick and Mark Steadman, to help with the growing support load and to help maintain the software. James, Ed and Mark also worked on some internal projects and a couple of things that, sadly, have still to see the light of day.

The team at Coriolis kept iDefrag and iPartition working across multiple major system updates, from 10.3 to 10.13, and across the PowerPC/Intel switchover (which was rather more work than just clicking a button and rebuilding); we worked around some nasty bugs in Mac OS X, and indeed in third-party hardware and device drivers; and all the while we tried hard to answer support queries promptly, professionally and courteously.

Changes to the Mac, beginning with the adoption of SSDs, saw sales of the company's core products, iDefrag in particular, enter a slow decline. The final nails in the coffin were the decision of Apple to switch to its new filesystem, APFS, the volume format for which was totally undocumented until the week before macOS Mojave shipped, and the increasingly draconian security controls that made it harder for third-party utility software to function in a manner end users would find acceptable. In early 2019, Alastair finally took the decision to shut down the company he'd founded nearly 15 years previously.


Below you can find copies of Coriolis Systems' software, together with working license keys. Hopefully this will prevent the work we did at Coriolis from disappearing altogether.

Note that all software is provided as-is and with no warranty. We can't accept any liability for anything you may do with it or that may happen when you use it; if you think that will be an issue for you, don't use it. There is no technical support.

If you find this software useful and want to express your gratitude by sending me a donation for hosting it here, you can do that via PayPal

iDefrag 1.7.3
Mac OS X 10.3
iDefrag 2.0.5
Mac OS X 10.4–10.5
iDefrag 2.2.8
Mac OS X 10.6–10.9
iDefrag 5.1.3
macOS 10.10–10.11
iDefrag 5.3.1
macOS 10.12–10.13
iPartition 3.3.1
Mac OS X 10.4–10.5
iPartition 3.4.5
Mac OS X 10.6–10.9
iPartition 3.5.1
macOS 10.10–10.11
iPartition 3.6.2
macOS 10.12–10.13
Mac OS X 10.9+
Mac OS X 10.6+
Mac OS X 10.6+