I've said it countless times: it's not a question of if you will lose data, but when. Media, such as hard drives, eventually fails. Or you can make the kind of mistake that results in deleted folders or erased disks. And files can simply get corrupted. There are two things you need to do to ensure you don't lose data: back up your files regularly, and use software to diagnose and correct problems before they become serious.
Since 1998, Alsoft's DiskWarrior has been the go-to tool for fixing disk corruption on Macs. It's been eight years since the last update to DiskWarrior. At the time, I reviewed DiskWarrior 4 and gave it the highest rating, five mice. It has saved my data, and fixed hard drive issues, many times over the years.
DiskWarrior does one thing, and does it well: it optimizes and repairs disk directories, which contain the information that tells your Mac where files are stored on the disks attached to it. If directories become corrupted, you can lose files. While your data may still be on a disk, the Mac is no longer capable of finding it. DiskWarrior works both as preventive medicine — to fix errors before they become serious — and to correct more serious errors and help recover files when things get really bad.
Goodbye CD, hello flash drive
DiskWarrior 5 is a major update to this essential app and includes a number of new features. The most visible is that it no longer comes on a CD. You now get a bootable flash drive that contains the software. To optimize or repair a startup volume, you boot from the flash drive. To work on any other connected disk, you can copy the software to your Mac and run it from there.
However, because of the way Macs now work, you can only start up your computer directly from the flash drive if it was originally delivered with OS X 10.4, 10.5, or 10.6. (See more detailed requirements for running DiskWarrior.) To boot from the DiskWarrior flash drive on a newer Mac, you need to boot to your Recovery partition and then run a Terminal command to launch the software. You can also use the DiskWarrior Recovery Maker to update the flash drive to be able to boot your Mac directly. (Or, better yet, a different flash drive, 2 GB or larger, so you can keep the original intact.)
When you boot from the updated flash drive, which replicates your Recovery partition, DiskWarrior appears in the OS X Utilities window. Click it to launch it, and then select a disk to analyze, optimize, and repair.
Sign up for CIO Asia eNewsletters.