This is particularly true in these days of constant security updates as replacing operating system components not only increases the potential for 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 above all, it takes longer to get your work done.

iDefrag defragments and optimizes your disk for improved performance. Add in the size of some of the files in common use today, especially music, video, graphics and computer games, and even the best filesystem has trouble keeping things contiguous.


  • 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.


  • Mac OS X 10.3 or later
  • 500MHz PowerPC G3 or better
  • 512MB RAM.