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I have a computer which is almost 10 years old now. It uses a hard disk which is also almost 10 years old. Recently I had installed a software called 'Hard Disk Sentinel' which checks the health of the hard disk. The software told me that that the health of my hard disk was 14%. It said:

There are 528 bad sectors on the disk surface. The contents of these sectors were moved to the spare area. 4089 errors occurred during data transfer.

In case of sudden system crash, reboot, blue-screen-of-death, inaccessible file(s)/folder(s), it is recommended to verify data and power cables, connections and if possible try different cables to prevent further problems. It is recommended to examine the log of the disk regularly. All new problems found will be logged there.

It is recommended to backup immediately to prevent data loss.

But my computer is almost 10 years old and I have not had any data loss whatsoever. All my photos, videos and documents are there in their respective disks and all open and run smoothly. As a matter of fact it's been 3 weeks now since I scanned my hard disk and found out there were bad sectors and still there has not been any data loss.

Should I be worried by about my hard disk and if so why has not there been any data loss in my hard disk?

P.S.: All of my drives other than Local Disk (C:) are HDDs and their health is being shown as 14% and all the stuff which the software is saying is about those HDDs. However my Local Disk (C:) is an SSD and it's health is 100%. It has no problems.

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  • Back up your data to an external drive. Then, clone the failing drive to a new drive. Macrium Reflect Free does a great job. I've used it many times. You can then bag the failing drive and hang on to it as it's still accessible.
    – Tracy LF
    Aug 7, 2022 at 4:50

4 Answers 4

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But my computer is almost 10 years old and I have not had any data loss whatsoever. All my photos, videos and documents are there in their respective disks and all open and run smoothly.

That's because "The contents of these sectors were moved to the spare area.". All modern disks have spare sectors for this purpose. However, there's a limited number of them, and when they run out, your harddisk can no longer do that.

On top, getting more and more bad sectors is an indicator that there is a problem somewhere in the disk (misalignment, a very slight mechanical problem, whatever). This tends to get worse exponentially, and what usually happens is one day everything is working fine, and the next day you turn on your harddisk it can hardly read anything at all.

So now is the time to buy a new harddisk, copy all your important files over, and start using the new harddisk instead of the old one for all your data.

You can still use the old one for things that can be easily replaced from somewhere else (e.g., applications downloaded from the Internet).

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    Also: check if backups are being made regularly and are restorable.
    – gronostaj
    Mar 29, 2022 at 6:57
  • hard drive will only reallocate to spare IF data can be recovered (ECC, ERP) or if pending sector is written to. So spare sector pool and sector reallocation do not mean you'll not see bad sectors even with plenty of spares to spare. Oct 23, 2022 at 13:40
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Yes, it can. Increasing numbers of sectors failing means the drive is in early stages of failure. It doesn't mean it WILL fail tomorrow, but bad sectors piling up is a primary symptom of ongoing disk failure.

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Can Bad sectors in Hard Drive really cause Data loss?

Yes, they can. It depends upon what worked and what did not. When it comes to Bad Sectors there are some related critical S.M.A.R.T. parameters.

Reallocated Sector count - Bad sectors that generally have been remapped to spare area.

Current Pending Sector Count - Unstable sectors on the hard disk that are yet to be remapped or reallocated. Sometimes these are SOFT errors and a full disk low-level reformat may correct it.

Uncorrectable Sector Count - Number of uncorrectable errors while reading or writing a sector on the hard drive. These may cause permanent data loss.

If the system completely fails to read a bad sector it may not at all reallocate it. In that case the entity e.g. a File that was residing there will get corrupted.

By chance you may be lucky or the issue is latent for now. One fine day you may open a photo and find that the file is actually corrupted. I would be interested to see your full S.M.A.R.T. report. Showing these 3 critical parameters among all others.

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Yes, they most certainly can and frequently are cause for loss of data. It's not uncommon for data recovery labs to have their special hardware designed to clone drives with bad sectors working around the clock, full time. This hardware directly communicates with the drives often using vendor specific commands (VSC) and are highly tweakable (timeouts, skip heads, various resets etc.).

Several DeepSpar DDI units in action

Of course we can lose the data stored inside the sector that goes bad. If this happens to be a sector that stores a user file, say a JPEG that lost sector will cause the JPEG to corrupt. Also the operating system rather than opening the file will probably not open it and instead present an error message.

We have a more serious problem if we have one or more bad sectors that store file system meta data. It's not uncommon for an operating system like Windows trying to read such sectors over and over causing the system to lock up. We basically lose the ability to access the entire volume with a few strategically placed bad sectors.

But it can be even worse. For example, in the past certain drives with certain firmware issue that kept trying to reallocate bad sectors. These reallocations are recorded in a certain part inside the system area (SA), and continued reallocation caused these areas to overflow and effectively overwrite crucial data inside the SA. And since firmware is stored on the disk's surface as well, these sectors can go bad themselves rendering the drive useless.

Also bad sectors in SSD, SD card and USB flash drives often cause the drive to 'go stupid', the firmware gets so busy handling the anomalies that it leaves no time to respond to read or write commands.

Recovery.

If a drive is still responding to commands the first thing we need to do is clone or image a drive. As mentioned a data recovery lab uses specially designed hardware. If you want to try yourself you need to use software that was designed for this task. Examples are ddrescue and HDDSuperClone where the latter is more advanced.

Key with cloning is, is to avoid and spend as little time as possible on bad sectors during a first phase. Get all data that can still be read while stressing a drive as little as possible.

If key file system meta data was knocked out by bad sectors, next stage is virtually reconstructing those as much as possible using file recovery software (which we use on the clone / disk image, not the patient drive). A data recovery lab often uses software that's highly integrated with their special hardware.

As a last step repair can be attempted of individual files that were recovered but partially were in bad areas (repair of badly damaged photo).

repair badly damaged photo

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  • can downvoter explain the downvote? Oct 23, 2022 at 14:31

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