No matter how well prepared you are, at some point changes are you’ll lose some data. At that point it's Disk Drill, a data recovery app for Mac OS X (10.6.8 or higher), to the rescue. Recently, it's been revved to the (awkwardly dubbed) version 2.4.437.
Developed by Cleverfiles, the software recovers damaged and deleted data (photos, music, documents, applications, specific Mac OS X and other file formats) from external or internal hard drives, memory cards, iPods, etc. It helps you undelete Mac OS X files using two Mac recovery methods: Quick or Deep scanning; the latter -- available on the "pro" version of Disk Drill -- is for low-level data recovery.
You can recover data from any drive you can mount in Mac OS X. What's more, you can insert any memory card or USB drive into your Mac directly or by using a card reader, scan it with Disk Drill, and recover any deleted data.
Disk Drill’s user interface sports a convenient universal Recover button that allows for one-click recovery. The utility’s Rebuild function attempts to rebuild the catalogs of HFS+ partitions that won’t mount correctly. Disk Drill uses the existing partition header to locate the B-tree catalog of the HFS+ partition and optimizes it by rebuilding its B-tree structure. The newly rebuilt directory is mounted as a virtual disk image with all the original files and folders that can be recovered.
The Universal Partition Search allows you to recover partitions on HFS+, FAT and NTFS volumes. It works on a disk level, and treats the disk as binary entity, quickly scanning the disk for signatures of known partition headers. Any found partition is mounted as a virtual disk image and can then be scanned for all original files and folders.
The Scan for Lost HFS+ Partition method finds and recovers HFS+ partitions that have been reformatted. It scans a partition for the backup copy of the HFS+ partition header. It then uses the backup copy to attempt to recover the previous data structures. Any found partition is — yep, you guessed it — mounted as a virtual Disk Image and can then be scanned for all original files and folders.
Users of registered versions of Disk Drill will be able to mount their scan results as a disk and preview them in Finder, using native applications. No more having to use the QuickLook preview function.
Version 4.437 adds DGN (Adobe Lightroom Raw image) recover via Deep Scan. It also provides bad sector management, Quick Scan internal procedures, and software protection/activation.
Disk Drill comes in two versions. The free, basic version protects files from accidental deletion with Recovery Vault and recovers lost data from Mac disks. Disk Drill PRO (US$89) features a number of advanced scanning modes for data recovery of FAT, NTFS, HFS/HFS+, other file systems. It lets you rescue files that were deleted long ago or pre-reformatting of your drive.