OmniDiskSweeper is a free utility for finding and deleting big files that are taking up precious hard drive space.
OmniDiskSweeper is fast, efficient and a great way to recover lost disk space. When you start OmniDiskSweeper, you're presented with a list of disks attached to your Mac. Simply double click on one, and a new window opens with a column view listing every folder and file you can access, which it sorts by size. The free space remaining on the disk and the re-ordering of folders are automatically recalculated as you delete old, space-hogging stuff.
In a glance, OmniDiskSweeper helps you identify the biggest culprits (such as Lightroom cached files) that are taking up valuable space. It must be used with caution however - once you hit the Destroy button, there's no undo button. Most recently, OmniDiskSweeper has been made free by the developers making it an even more attractive utility.
If you're struggling for hard drive space, you can't do much worse than free OmniDiskSweeper.