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Recovering Partitions on a Corrupted Hard Drive

Recovering Partitions on a Corrupted Hard Drive

In our previous articles, we’ve been talking about recovering deleted files, fixing accidental damage and dealing with formatted or inaccessible disks. Today we’re going to handle a situation where the most sensitive part of the hard drive gets damaged; the part that contains information about the disk, its volumes and their configuration.

Recovering Partitions on a Corrupted Hard Drive

Damaged Boot Record and Partition Table

As you may already know, information stored on the hard drive is organized in a certain logical way. Most operating systems including Windows, Linux and Mac OS will initialize a physical storage device by creating one or more logical disks, which are also called volumes or partitions. The process is called “partitioning”. These logical volumes (disks, partitions) are further initialized by formatting. By formatting the volume, the system is creating an empty file system which, in turn, will contain records pointing to actual files stored somewhere on the disk.

The first thing an operating system does when mounting a physical hard drive is looking for system records that contain information about the logical volumes or partitions. While different operating systems may use different formats for that (e.g. MBR partition table in Windows or GUID Partition Table in Mac OS X), the system must be able to read that information before it is able to mount the volumes as drive letters.

But what if that information is damaged or is no longer available?

All information about the logical volumes or partitions located on the physical hard drive is stored in the few initial sectors. This means that damaging just a few small sectors will inevitably render the entire hard drive inaccessible. A variety of things may cause damage to the disk’s highly sensitive system structures, but the outcome is always the same: inaccessible disk requiring a repair.

Repairing Disks with Inaccessible Partition Tables

As you can see, a relatively small damage can cause a big trouble, rendering the entire storage device inaccessible. However, despite all the trouble this situation is in fact relatively harmless. If the Master Boot Record or the GUID Partition Table are the only areas damaged (or erased) on your hard drive, the rest of your data is sitting safely where it originally was. By applying a proper technique while using the right tools, and considering that no further damage was done to the disk, you can hope for complete recovery with nearly a 100% success rate.

The Right Technique

Before we mention any tools you will need to recover the disk, make sure you understand one thing. A proper technique is as important as the use of a proper tool. If you start rushing and attempt to ‘recover’ the disk by re-partitioning and/or formatting the device, you will be making things much more complicated for the person who is going to do the recovery. Don’t re-partition the disk. Don’t format it. Don’t write anything on it. Just leave it along until you install a partition recovery tool, read the manual and make sure you understand how to use it.

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Partition Recovery Tools

There are several partition recovery tools on the market. We’re not trying to review a particular application or make a feature/performance comparison. We just need a no-frills tool that gets the job done. For that purpose, we settled on RS Partition Recovery. This tool can recover information from damaged disks even if the disk is inaccessible and has no readable partitions available. Describing the product is not the purpose of this text, so if you need more information about the tool, you’re more than welcome to check out https://recoverhdd.com/data-recovery/partition-recovery.html

Recovering Partitions: Making a Backup Disk Image

Depending on how much exactly your data is worth to you, you may want to make a backup copy of your entire hard drive by capturing a virtual disk image. Partition recovery tools can normally do that no problem. Some more advanced tools can even use the virtual disk image to recover your data instead of the actual physical device. If you have a lot of highly valuable information stored on that disk, making a backup copy before you proceed with the recovery is a highly recommended step. If, however, you are about to recover a disk filled with data that can be easily replaced (e.g. a system hard drive with no documents, photo albums or other information that is difficult or impossible to re-create), then you can save a few hours by doing the recovery right on the disk.

Recover the Data

The ultimate purpose of partition recovery is restoring all of your data. For this reason, do not attempt to repair the broken partition table before you are absolutely sure your valuable information is safe. Otherwise, you’ll be facing the risk of an unsuccessful recovery attempt damaging your data instead of saving it.

In order to recover the data, run RS Partition Recovery, launch the Recovery Wizard, and choose the complete recovery option. When prompted for a disk volume or a physical device to recover, choose the “Physical device” option and select the hard drive containing the broken partition table.

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What happens next is a lengthy scanning. RS Partition Recovery will employ heuristic techniques and content-aware search in order to detect the exact partitioning configuration of your hard drive. The tool will search for partitions by reading the entire disk surface and looking for certain characteristic signature identifying supported file systems. RS Partition Recovery supports all Windows file systems (FAT and NTFS), ensuring that all volumes formatted with these file systems can be successfully located.

After locating the volumes, RS Partition Recovery will display them in a window, allowing you to extract information (files and folders) from each volume. You’ll be prompted for a location to save the files and folders to. Make sure the target location has enough free space available to receive all the files.

Repair Partitions

Actually repairing the damaged or missing partition tables can be performed with an open-source tool called TestDisk (www.cgsecurity.org/wiki/TestDisk). Unlike RS Partition Recovery, this is a command-line tool that requires good understanding of what you are doing, and why. In a word, you’ll use the tool to analyze the disk and attempt to re-create the original partition table, in best-case scenario fixing the entire issue.

One question I’ve been asked a lot is why bother with RS Partition Recovery? Why not use TestDisk instead, immediately after one detects the damage?

This is a good question that deserves an elaborate answer. The two partition recovery tools fulfil completely different purposes. RS Partition Recovery recovers your valuable information as in files and folders, documents and pictures. If everything else fails, by using RS Partition Recovery you will still have a copy of all information. Restoring it to another (healthy) disk will be a no frills job in matter of hours.

TestDisk, on the other hand, does not touch any file on the disk. Instead, it will attempt to fix the original partition table, recovering missing partitions, boot sectors and file tables from their backup locations on the original disk. If this fails, or if there is no backup, or if the backup refers to a different partition configuration, you’ll be SOL. However, you may still be able to use RS Partition Recovery even if TestDisk fails to rebuild the original partition structures.