Step 1. Download Data Recovery for Mac and install it.
To recover external hard drive on Mac, connect your media in advance.
Step 2. Select from the recovery modes
Here selects "Lost File Recovery" in the Home Window.
Step 3. Select the volume where you lost the files. Click "Scan".
Step 4. Preview the files and click "Recover". Choose a path to save the files.
How to Recover Data from Dead, Corrupt Mac Hard Disk?
An internal Mac hard drive can go "dead" when its own operating system no longer integrates with the OS X operating system driving the computer. Recover data from corrupt Mac hard drive by using a built-in utility to connect it directly to another Mac, which is "Target Mode".
Step 1. Remove all cables from the Mac that has the dead hard drive. Place the Mac next to a second Mac. Reattach the power cable and the keyboard to the Mac that has the dead hard drive. Plug the power cable into a wall socket.
Step 2. Turn on the second Mac. Wait for the desktop to appear on the screen. Connect an end of the Firewire cable to the Firewire input on the back of each Mac.
Step 3. Press and hold down the "T" key on the keyboard of the Mac that has the dead hard drive. Press the power button momentarily to turn the Mac on while still holding down the "T" key.
Step 4. Release the "T" key when an icon of the dead hard drive appears on the desktop of the second Mac.
Step 5. Double-click the icon of the dead hard drive to open its window. Drag any or all of the data out of the window onto the desktop. Wait as a copy progress bar appears, fills in from left to right and then disappears---this could take anywhere from a few minutes to a few hours, depending upon the amount of data that is being taken off the dead hard drive.
Step 6. Drag the icon of the dead hard drive to the trash once the copy progress bar has disappeared. Press and hold down the power button on the Mac that has the dead hard drive until you hear it shut itself off---this will only take a few seconds.
Step 7. Disconnect the Firewire cables from both Macs. Remove the keyboard and power cables from the Mac that has the dead hard drive. Place the Mac back in its original position and reattach the cables.
For all, you have learnt how to perform Mac Hard disk recovery successfully.
Actually, it is highly recommended you to back up all important documents on a regular basis. It is the most convenient way for you to get back the data if you accidently lose it.
How to back up files on Mac OS X
There are several ways to back up and restore files on Mac OS X, using Time Machine, Disk Utility, iDisk and iWork.com. Here we recommend Time Machine. You should set up Time Machine backups using an external drive
1. Connect an external drive to your Mac via Thunderbolt, FireWire or USB.
2. Click "Use a Backup Disk" to confirm you want to use the drive for Time Machine backups. Time Machine preferences will then open with this drive selected as your backup destination.
If you want to encrypt the Time Machine backup external drive, you can check "Encrypt Backup Disk".
Data Recovery for Mac can also be applied to recover this backup disk. Try to protect this backup files and restore the files on Mac.