Disk recovery are two words one never hopes to have to utter during their IT career. The process is ultimately very time-consuming and quite costly, plus it's also almost completely avoidable by implementing a solid, scheduled backup solution and taking some care to follow safe computing habits and best practices.
However, in the event of a catastrophic failure that results in a corrupt or failed drive, all is not lost just yet. Thankfully (for end users), data recovery takes on several levels due to the nature of failure in the hard disk. For many individuals, the first cause is also the most common: deleted or "lost" files. This is followed by the next level of failure, which typically occurs due to OS-level system file corruption or the occasional malware infection. These render the drive physically operable, yet the file structures or tables have been rewritten or deleted altogether, so the files unable to be located — almost like a book with a table of contents.
The last level is by far the worst and equally most expensive: hardware failure. This can be anything from clicking noises (aka "the click of death") to grinding noises or even the loss of power to the drive. In most cases, by the time the disk reaches this level, there's little to be done but accept the loss or take it to a forensic lab for scientific recovery and/or repair.
This article will deal specifically with levels one and two, since they're the most common and the easiest to recover data from. In many cases, the data may even be recoverable by the end user (or system admin) with a specialized recovery software application.
There are numerous types of data recovery software available and even apps that are designed to support multiple OSs — ones that are Linux-based or boot into a specialized DOS-like environment from Live CDs — but they may or may not support all of the native features of OS X. In this article, we'll focus only on software that runs natively on OS X.
Without further adieu, here are three data recovery applications for OS X.
EaseUS began developing data recovery software for Microsoft, they then expanded the Data Recovery Wizard line to include native support for Apple OS X with three offerings: Free, Pro, and Unlimited versions respectively.
The Freeware version is not a time-trial, though it is limited to a maximum recovery of 2 GB of restored data. Geared mainly toward recovering from accidental file deletions or disk formats, EaseUS' product also includes support for data corruption brought about by unexpected crashes, loss of power, or removing a device without first unmounting it.
File support includes most of the commonly used image, music, video, and document file types for a variety of applications. In addition to supporting the OS X native HFS+ file system, Windows-compatible FAT/FAT32, and exFAT file systems are supported for use with USB flash drive and external hard drives that are also used by Apple computers.
The Free and Pro versions are virtually identical in their offering, except that the Pro license ($89.99) allows for unlimited data recovery and lifetime technical support. For enterprise support, an Unlimited license ($499) is required, which allows for commercial usage within a corporation or when providing technical support to clients.
Unfortunately, EaseUS Data Recovery Wizard for Mac lacks the deeper support for data loss as those found in more commercial suites, especially pertaining to corruption from lost partition table entries or modified boot sectors. Yet, the simple-to-use scanning engine that's built in to EaseUS' product is both effective and fast, while offering full support for OS X Mavericks too.
Prosoft's Data Rescue 3 ($99) is arguably the most well-known data recovery application for OS X — and for good reason. It works well and is good at what it does: recovering your lost or deleted data from a wide-range of level one and two types of data loss. It is also the only commercial data recovery application that has a variant available in Apple's Mac App Store at a lower price point ($59.99).
DR3 is two components in one: a package that installs itself on your Mac computer for native, client scanning of local and externally connected drives and a bootable emergency DVD that can be used to boot from in the event that the damage to the hard disk is too severe to boot into the live OS X environment.
A feature unique to DR3 and one that sets it apart from other utilities is its scanning engine, which not only scans a drive for physical and logical structure damage but creates a full clone of the failing drive onto an image that is then stored locally on your computer or an external disk. Recovery then commences from the clean image so as to not damage the malfunctioning drive further. This particular technique is used by security and system admins prior to conducting forensics on physical media. By doing so, the original drive is protected from contamination, much like detectives preserve the scene of a crime.
Another important feature is its FileIQ, which helps the app "learn" file types and add them to an internal database used by the DR3 when performing scans. This is a huge benefit for developers or enterprises that rely extensively on in-house developed code, and the code may include the use of proprietary file types when used with corporate applications.
Prosoft has been creating data recovery software since 1985. Sadly, Data Rescue 3 has not been updated since 2011. I have successfully used the full-version application available from their website on OS X 10.9 to recover data in the past — the Mac App Store version has a larger disclaimer, stating that it's not compatible with OS X 10.8 (Mountain Lion) or later. This is a bit of a let down, since this particular application works quite well and has garnered several awards in the past for being exceptionally good at data recovery.
DiskWarrior by Alsoft ($99.95) is the de facto data recovery software that's used for more than just data recovery. DW, like Data Rescue 3 above, includes both an installer for native use on OS X computers and a bootable DVD that can be used to boot the computer and run a full-scan on the hard drive to correct any software-based disk issues that may be present, or it can recover documents from damaged directories.
A feature used by DiskWarrior — in conjunction with scanning the drive for errors — allows it to rebuild disk directories and the files/folders contained within them, allowing one to not only recover documents but also fix mysterious errors that might otherwise go unnoticed by other applications, including Apple's own Disk Utility.
The application is regularly updated, includes access to technical support via telephone, and has garnered countless 5-star awards for its way of saving people's precious data. As an added value, DiskWarrior supports the latest Fusion Drive from Apple, and it's OS X Mavericks (10.9) compatible as well.
Alsoft has also seen it fit to include support for disk encryption for users of Apple's File Vault 2. The DiskWarrior application can be run directly from OS X natively — or alternatively, the hard disk may be decrypted first, then have the application run from the boot DVD if startup is not available.
DiskWarrior when launched directly from OS X, does not have the ability to repair the startup disk, which is why the bootable DVD is included. But what does one do if there are no optical drives or a spare external drive from which to launch DW? Luckily, this is often the exception and not the rule. In most cases, users will be pleasantly surprised to find out that DiskWarrior can resolve a great many issues that cause level one and two data loss —-with the occasional resolving of very minor level three-related issues.
As with any software category, there are numerous applications to choose from. Some are better at recovering data then others, others are aimed at forensics experts, and even others are open source and therefore ubiquitous in their usage across platforms.
Finding the application that helps you to recover the data that's been lost is two parts trial and error and one part magic. The magic comes in the form of each case being unique from the rest. While I've personally had very good luck with recovering data from deleted or formatted partitions, there are those inevitable times when I have to report to a client that, unfortunately, the drive was too forgone to make recovery through software means a viable possibility. For those moments, we are thankful for our backups... or the professionals that specialize in mechanical data recovery for consumers and businesses alike.
Which data recovery application do you recommend for OS X? Share your opinion in the discussion thread below.
Jesus Vigo is a Network Administrator by day and owner of Mac|Jesus, LLC, specializing in Mac and Windows integration and providing solutions to small- and medium-size businesses. He brings 15 years of experience and multiple certifications from several vendors, including Apple and CompTIA.