Sunday, July 31, 2011

How to repair a bad sector that can't be repaired by CHKDSK?

Here's a simple tool to recover your data and repair bad sectors.

I always thought that disk errors and bad sectors are the only errors that threaten a hard disk (aside from a total hard disk crash, of course). And I always believed that this error could easily be fixed by CHKDSK. However, recently, I encountered lots of disk errors that recur even after a thorough (and very time consuming) CHKDSK.
This article will talk, in length, about disk errors and how to fix them. It will also outline a solution on How to repair a bad sector that can't be repaired by CHKDSK.

What is a bad sector?

For the purpose of this article, we will focus only on mechanical disk drives.
Bad sectors are defective sections in the disk that cannot be accessed. It doesn’t respond to read or write requests from the operating system (or from any program, for that matter) and often cause trouble.

There are two types of bad sectors:

  • Logical bad sector

This type of bad sector is often referred to as “soft” bad sector because it is caused by an error in the data that keeps a record of the sector. Often, the sector is merely corrupted and cannot be accessed by a program or the operating system. This error is easily fixed by formatting the drive or by performing a CHKDSK.
  • Physical bad sector

This is a more serious type of bad sector. From the name, the nature of the error is physical thus it’s also known as the “hard” bad sector.
Rarely, this is caused by either the drive’s head touching the surface of the disk or a dust settling on the disk.
The drives head only touches the surface of the disk when the disk is subject to a shock, say from falling or from being bumped. Dust do not often settle on the disk since the insides of the hard drive is meant to be dust free. Unless, otherwise, the disk has been opened deliberately.
A bad sector caused by the abovementioned conditions CAN’T BE REPAIRED or recovered.
Most often, however, a physical bad sector occurs due to an inconsistency in the magnetic alignment of the molecules in the surface of the disk. Frustratingly, a hard format or a CHKDSK can’t deal with this. Until recently, this type of bad sector is considered irreparable.
I’ve had many disks in the past which suffered from this type of error, and I’ve recently successfully recovered them.

How a bad sector manifests

How can you tell whether your hard drive has a bad sector?
The easiest way is to read the RAID report. RAID is a feature of hard drives that displays the number of bad sectorsusually, hard bad sectors. Another way is to perform a CHKDSK.
You can, however, tell that your hard disk has a bad sector from these subtle cues:

Slower than before performance

This is a bit tricky because computer performance (and speed) is caused by many factors. But, say you ruled out various factors such as RAM capacity, disk drive write and read speeds and processing power.
A sudden change in the performance of a computer and an increase in the frequency of lags can be caused by a bad sector.

Computer freezes at any point while you are using the computer

This, too, may be caused by other factors. But a bad sector, both hard and soft, can sometimes make your computer freeze.
This may be due to sectors containing important system files going bad. Sometimes, the computer even restarts itself. If the computer freeze and the restart are caused by a bad sector, you won’t be able to boot your computer up. If this happens, there’s a great chance your disk has a bad sector.

Computer freezes when you access certain files or folders in your computer

Bad sectors are inaccessible parts of the disk. But this does not mean that the operating system won’t try to access the file or data contained in the sector. Often, the operating system will retry a number of times. This causes the lag or the freeze.
After some time, the computer displays “file access” related error.

Unusual sound can be heard from the hard disk

This is a classic tell-tale manifestation of a bad sector. However, if you hear a mouse-like sound emanating from your hard disk, it’s most probably a hard bad sector.
While I’ve had experience being unable to recover hard disks that screeches, I have lots of hard drives that are operating until now which are successfully recovered.

Performing a CHKDSK (the easy way)

Let’s assume you haven’t tried CHKDSK yet. Here are the steps for you to recover or repair bad sectors on your hard drive:
  1. Open "My Computer" (for XP) or "Computer" (for Vista and 7).
  2. Right click the hard disk you suspect has the error.
  3. Select tools.
  4. Select Check Disk.
  5. Check "Check for and Attempt Recovery of Bad Sectors."
Note: In case the hard disk that you want to check for errors with are currently used by the operating system, your computer may prompt you to schedule the Check Disk in the next start up of the computer.
  1. Wait.
  2. Errors solved. Bad sectors recovered.

Performing a CHKDSK using Command Prompt (CMD)

Sometimes you won’t be able to access the disk via Explorer. Sometimes, the computer freezes after right click on the disk. In this case, you can perform (with increased chances for success) a CHKDSK via the Command Prompt.
  1. Press Start
  2. Locate Command Prompt (Start>Accessories>Command Prompt) or Press Windows Key + R and type "cmd."
  3. Type in the letter of the disk you want to check with.
  4. Press enter.
  5. Type "CHKDSK /F" minus the quotation marks.
  6. Press enter.
Note: In case the hard disk that you want to check for errors are currently used by the operating system, your computer will prompt you to schedule the Check Disk in the next start up of the computer.
  1. Wait.
  2. Errors solved. Bad sectors recovered.

Recovering the Hard Disk Using a Third Party Software

Soft (or logical bad sectors) are often easily repaired by a CHKDSK. If CHKDSK fails to repair the bad sector, another (more harsh method) is to format the drive. This will overwrite existing data in the sector with zeros and ones and will fix the drive.
Hard (or physical bad sectors) are trickier to repair. There are a lot of software that claims that they can repair bad sectors, but all they just do is write zeros and ones on the disk.
You can secure a trial version of the software here:
Download Trial Version
Which will give you a chance to check your hard drive for errors but the repair mechanism is limited.
Alternatively, you can purchase a license here:

Buy HDD Regenerator

My Personal Experience

Unless you resort to a pricier alternative which is SSD drives, chances are, you’ll encounter bad sectors along the way.
I’ve had some hard disks which I declared irrecoverable in the past. Some, I even threw away. Fortunately, I have some which I recovered and use up until today.
It even extended the lifespan of my disks. Manufacturers claim that their disk can last up to 6 years (or so). I have one that I’ve been using since 2007. It failed many times, but I was able to recover the drive successfully (every time) using HDD Regenerator.
It’s not cheap, but the developer provides lifetime license. Mechanical (or hybrid SSD-HDD drives) remain the most economical storage solution. If you plan on keeping your old hard drives or extending their lifespan or if you want to recover data from your past drives, HDD Regenerator is a viable long-term option.
Data recovery companies charge high for a single service. You won’t need to enlist their services and pay a hefty amount if you can recover them yourself.
I say HDD Regenerator is the ONLY effective solution for bad-sector related disk failure.


If you think this article helped you in a way or if you have questions or clarifications, feel free to reach us out in the comment section below. I hope this helps.

12 comments:
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  1. nice info! i'd like a copy of that regenerator!

    ReplyDelete
    Replies
    1. I updated the article and included a link to copy.

      Delete
  2. can i have a copy of that HDD regenerator?

    ReplyDelete
  3. I need a copy of the HDD regenerator

    ReplyDelete
  4. I desperately need a copy of this utility, thanks in advance.

    ReplyDelete
  5. I would appreciate a copy - thanks

    ReplyDelete
  6. Chkdsk did not work and I haven't been able to buy another computer so my hard drive is 8 years old. I don't want to lose my files that I didn't back up especially my children's pictures, and I can't afford HDD generator. Can you please send me a copy?

    ReplyDelete
  7. All the steps you outlined did not work. Can you please provide me a copy?

    ReplyDelete
  8. All the steps you outlined did not work. Can you please provide me a copy?

    ReplyDelete
  9. All the steps you outlined did not work. Can you please provide me with a copy?

    ReplyDelete
    Replies
    1. I updated the article and included a link to copy.

      Delete