File Recovery with Free Software

Ack! The computer ate my term paper! We've all been there at some point. You delete an important file, somehow it skips your Recycle Bin altogether, and for all practical purposes, it's disappeared into the ether. But before you hit the big red panic button, there's a very good chance that your file is still alive and kicking somewhere on your hard drive—you just need to know how to find it. With the right tools, finding and recovering that deleted file can be as simple as a few clicks of your mouse.
Part I: The Overview
Ok, so you've lost an important file. Don't panic. Take a breath, and let's see if we can find it. Before you go into full-on file recovery mode, make sure you double-check the folder you had saved it in and the Recycle Bin or Trash. Still nothing?
1. Stop What You're Doing
When your operating system deletes a file, all it really does is mark the space on your hard drive that your file occupies as free space. It's still there, but your computer is now perfectly happy to write new data on top of it—at which point the file recovery process becomes a lot more difficult. That means you should do as little computing as possible until you find the file you're looking for, since every time you save a new file—every time your computer writes information to your hard drive—your chances of recovering the file go down.
2. Find the Right File Recovery Program
Windows: You've a lot of really great freeware options for file recovery if you're running Windows. Notable apps include Undelete Plus (original post), PC Inspector File Recovery (original post), and Restoration (original post). Undelete Plus is the most user-friendly option of the bunch, with advanced filtering options that make it easy to find your needle of a file among the haystack of deleted garbage, but in my tests I found both Restoration and PC Inspector File Recovery to be more effective at recovering files. (Of course, your mileage may vary.) As an added bonus, the bare bones Restoration is portable, which makes it an excellent addition to your thumb drive.

UPDATE: Per several readers advice, you may also want to check out Recuva (original post), another freeware Windows file recovery tool.

Mac: If you're on a Mac and aren't afraid to lay down a few bucks in the name of data recovery, the $99 Data Rescue II is the go-to application for file recovery with a friendly graphical interface.

photorec.pngAll Platforms: If you're not afraid to crack open a terminal window or command prompt, the free, cross-platform command-line tool PhotoRec (original post) is a crack shot at recovering photos (as the name implies) as well as virtually any other file type from your removable media or hard drives.
3. Recover Your Files
jumbled-files.pngOnce you've picked a tool, it's time to scan your hard drive for your lost file or files. This process varies depending on the app you're using, but it's basically the same for all of them: Just point the program at the hard drive or folder that was holding your missing file and start your scan. Once the scan is complete, you're going to see a big list of jumbled file names. Often most of these files are nothing more than system files that your operating system has created in the course of basic operation, and you won't need to worry about them. You're just looking for the file type and name that matches what you've lost.

Once you find what you're looking for, saving it is a matter of right-clicking the file and choosing where to save it.

Went through steps one through three and still aren't having any luck? It might be worth trying again with a different application, since there can be a lot of variation between apps. If you're still not having any luck, part two discusses a few other ways you can try addressing more specific problems when your data goes missing.
Part 2: More Specific Problems
Above you got a basic overview for recovering deleted files from your computer. Now we'll take a closer look at some more specific problems, methods of data recovery, and tools that may be of help in your quest for your elusive lost data.
Recover Files from a Wiped or Unbootable Hard Drive
hard-drive-pic.pngSo you didn't just accidentally delete a file or two and empty your Recycle Bin prematurely—instead you've got a whole hard drive worth of missing data. You can still use many of the applications mentioned above to recover files from these drives as long as you have or can get the hard drive into a bootable computer. For more details, check out how to recover files from a wiped hard drive with PhotoRec (original post) or how to recover data from a crashed hard drive with PC Inspector File Recovery (original post).

If you can't or don't know how to get your unbootable drive into another computer, a Linux live CD can be perfect for rescuing files. If the Linux route scares you off, give the popular BartPE (original post) a try.

Finally, if none of these options can even read your hard drive, you still might be able to get it working for just long enough with a few tricks of the data recovery trade, like putting the busted hard drive in the freezer.
Recover Lost Photos
zero-assumption-pic.pngIf you need to resurrect photos from a damaged flash memory card from your digital camera, you'll be happy to know that most of the applications listed in part one above will do the trick—you just need plug in your camera or insert the card into your computer's card reader before running your data recovery application of choice. That said, you can find other applications, like Zero Assumption Digital Image Recovery (original post), that are focused specifically on image recovery that you may want to add to your data recovery toolbox.
Recover Lost Word Documents
If your lost dissertation was saved as a Word document, you've got a few more interesting options for getting to your lost or deleted documents—read more about them here and here.
Recover Data from Scratched or Corrupted CDs and DVDs
scratched-cd.pngIf your munged data is sitting on optical media like a CD or DVD, the recovery process can be slightly different. Freeware application CD Recovery Toolbox (original post) is made specifically to read the portions of a CD that are readable in an effort to rescue as much data as possible from a damaged disc. If that doesn't work, you may want to give a look at the 30-day trial of shareware application CDCheck, as recommended by a reader. Then again, if scratches are the issue, you may be able to get away with simply fixing your scratched CD or DVD yourself.
Part 3: Don't Let This Happen Again
backup.pngWhatever the cause of your lost file, the best method of data recovery is a good preemptive data backup plan. If you're on Windows, we've taken you step-by-step through how to automatically back up your hard drive so that this sort of thing never happens again. If you're running a Mac, do yourself a favor: Get an external hard drive and flip the switch on the easy-to-use Time Machine. Linux users should check out backup options like FlyBack, TimeVault, or the time-honored rsync.

Have you ever raised deleted files from the hard drive graveyard? What software did you use to do it? Tell us your tales of file recovery victory and woe in the comments.