Always keep your System backed up. Software tools can not always recover lost data. Please read our post on how to backup your computer (disks). You can even take a backup on a cloud storage which is reliable too. Read How to backup your files using online backup services.
Bootable Live Disks
Linux Live CD/DVD (such as Knoppix/Ubuntu Live) – When the Hard Drive is non functioning, your system will not boot. If you have stored or want to access files that are there on the drive, the first thing to do is, boot your computer using Live CD/DVD distributed by Linux (Knoppix or any other Live OS CD). Live CD/DVD can boot your computer via CD/DVD and installing RAMDISK image (on RAM of course). Advantage here is, Live CD/DVD can mount your internal Hard Drive and you could explore files that are recoverable. This is really helpful and we have used this technique in the past with great success.
Hard Drive Consistency Checkers
If your Hard Drive is able to boot but you feel or see some disk related errors, it would be worthwhile to run Disk consistency checking software such as;
CHKDSK – A DOS/Windows utility that can find disk errors and fix.
Disk Utility – A Disk related tool for MAC OS X that can verify the integrity of the Disk.
fsck – a Disk consistency checker for the UNIX.
These software tools are capable of finding disk errors and possibly fix them. But, it should be noted that not all errors can be fixed by these tools, they are not miracle tools anyways
Data Files Recovery
Sometimes we accidentally delete important files only to regret later. Fortunately there are some free data recovery tools that can just undo deleted files.
Recuva recovers files deleted from your Windows computer, Recycle Bin, digital camera card, or MP3 player.
PhotoRec is another such tool.
After a break-in or seizure of computer systems or disks, forensic analysis can happen on the disk to understand the data or recover data from the disk. There are tools that can perform forensic analysis of the recovered disk from criminals etc.
The Coroner’s Toolkit (TCT) - TCT is a collection of programs by Dan Farmer and Wietse Venema for a post-mortem analysis of a UNIX system.
Forensic Toolkit (Commercial) – Data forensic software created by AccessData.
EnCase (Commercial) – Disk security and recovery experts.
Are there better tools? Did we miss any tool? Please have your comments below.