I have a WD hard disk (1 TB additional drive to my PC). For the last 10 days, surprisingly its accessing speed plunged. I thought something wrong with my PC first. Later on, I realized that I may be victim of bad sectors.

I used "Advanced system manager" to scan the disk which confirmed bad sectors on my disk. But it stuck on J: after 58%. I tried 2 times. It fixed bad sectors of H:, and I: was free from bad sectors. [I left the PC for processing at least for 16 -18 hours]

Now my PC started to work properly. But since i was worrying about my data, I tried widows disk scan utility who stuck again. [I left the PC for processing at least for 10 -12 hours]

Next time I tried "HDD Regenerator" who found 22 bad sectors. But it failed to repair same in windows mode. And since its bootable USB was not working, so I failed reparing at the time of system startup.

This time I tried programs from "Hiren Boot CD". One of the tool stuck after 58% done. I tried "WD diagnostic tool" who found errors on my drive and returned 007 response code. It recovery tool failed with response code 225 (as I remembered). So this time I again tried "HDD regenerator". Till 58% It was running fine and found around 34 bad sectors. He regenerated them too. But now onwards it is regularly finding bad sectors and regenerating sectors which is making me afraid.

Now my questions are;

  1. Whether scanning a HDD continuously for bad sectors can increase them?
  2. If a software find bad sectors and repair them then whether another application again report same bad sectors?
  3. Whether I must replace my hard disk.
  4. If I cut/copy data from this disk to new one, whether the bad sectors can be copied to. (It might look a stupid question, but I am able to backup smoothly. So I am doubtful)
  5. If a HDD gets bad sector (even if very less number of bad sectors) then the chance of HDD crash gets increased?

5 Answers 5


First off, bad sectors will not be copied over.

Most of the time, programs that claim to fix bad sectors do not fix them. What they do is find out where the bad sectors are and put police ropes all around them to prevent your system from writing data to those blocks. Does is work all of the time?, no.

You should replace the disk. You risk your data by not replacing the disk.

Copy everything as soon as possible.

You can also try to do a full format on the hard drive (once you get as much data off as possible). Sometimes a full format will help clear up any bad sectors, but is more of a long shot.

Scanning the HDD continuously should not increase bad sectors, but got, it'd be annoying to keep scanning drives with bad sectors.

One thing i've done in the past with a bad disk (more motor related) with is plugged it in outside of the computer. I had a pan of some water and ice sitting on the drive (after having it in the freezer for a bit). I kept the drive extremely cold and was able to copy over data.

  • I'll not dare to follow your last suggestion ;) But thankful for others. Commented Oct 1, 2011 at 4:48
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    If you need more information about your disks then check out CrystalDiskInfo, It's a pretty cool program. crystalmark.info/software/CrystalDiskInfo/index-e.html
    – kobaltz
    Commented Oct 1, 2011 at 4:53
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    Finally HDD regerator also stuck after finding 1500 bad sectors. I had exit from the program. Thanx suggesting the tool. I'll definetely try it today. I'll place the data to another drive. But should i don't relay on current HDD? Means should i never use it? Commented Oct 1, 2011 at 5:06
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    @articlestack If it has 1,500 bad sectors, then you shouldn't use it except to get your data off it as soon as possible. Its like the computer equivalent of car with no brakes - You wouldn't drive to work in car without brakes, don't use a hard drive with 1,500 bad sectors to store your data either ;-) Commented Oct 1, 2011 at 5:13
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    "… Scanning the HDD continuously should not increase bad sectors …" but it could increase the likelihood of automatic sector reallocation, which is not always a good thing. With an imperfect disk I should recommend as few reads as possible. Commented Apr 1, 2013 at 18:23

Seems everyone forgets that HDDs have spare sectors.

The HDD replaces bad sectors with these, but only when the bad sector is written to!
Also, the HDD itself decides on what sector is "bad", unreadable correctly.
That is, sectors have checksums so HDD firmware can detect "bad" sectors. (or more complex error checking mechanisms).
Additional detection obviously by other means inside the HDD.


  1. spare-sectors are limited, "how many" and "where" are well kept secret by manufacturer, but assumption is that they exist on the same track (circle, or cylinder). That is, no extra seek needed for read head, just a delay until the spare is under the read head.

  2. since "long ago" HDDS has had two internal lists of defects (bad sectors)

    • Factory List, constructed at factory before shipment

    • Grown List, defects "grown" while in customer usage

    "Long time Ago" one could read these lists, usually with "negative sector numbers" and/or writing some unlocking code to HDD controller. However, as this would give ordinary users information on HDD quality, the info was made more secret. (it also makes it possible for manufacturer to sort the HDDs in different quality classes, some for CIA, some for Google and the rest for you)

  3. HDDreg, HDD Regenerator clearly activates this spare-by-writing but clearly also does some other tricks to "save the data". Claims it "regenerates" by detecting,using, humping some "magnetic hysteresis" of the surface. Might be true, maybe not, but sounds like selling stuff. BEST TOOL ON MARKET!!

  4. However, some new HDDs "crash their own firmware" when a too defective surface. HDD disappears from OS, might lock the SATA,etc controller, etc deadly stuff (for rest of computer). Luckily power-off-on of just the HDD gets the controller-firmware running again (no need to reboot, but only if you're using hot-swappable SATA)

  5. Usual warning signals are "timeouts" and synchronized "clickings". (when HDD tries to recalibrate heads,etc but it doesnt work).
    IN a recent case it cycles through a click-click and frozen cycle.

    • 30-60sec drive runs, but clicks.
    • Then 3-4 minutes of "totally dead", keyboard,mouse,network, even HDD LED (ON). All of this obviously dependent on HDD firmware, SATA controller and Operating System.

Hope this helps understanding the "magic"

PS the actual physical sectors are now 4k byte, not 512 as before.

PPS the old AT command for "raw read of data and checksum" has now disappeared, as sectors now a more complicated thing.


Scanning a HDD continuously or often reading/writing at bad sectors may cause the bad sectors to propagate. You should isolate the bad sectors out of partitions, or mark them bad in file system.


Scanning a HDD continuously or often reading/writing at bad sectors may cause the bad sectors to propagate./

Or could

  • make the little magnets get better, taking them out of their hysteresis-lock
  • or maybe the write head is getting weak, replacing old good magnets with weak new ones.
  • or maybe the defects just grow by themselves

But obviously if the head servo is getting bad, doing anything will make things worse. SMART, SCSI info has an attribute for "bad servo" too


Scanning a HDD continuously/ is what some anti-virus programs and even operating systems already do. Additionally also "outside partitions" which is snart as that is one good place for viruses. (as are unused sectors inside partition, MFT tables,etc,etc)

Typically this starts after Computer has been idle for a while, for example middle of night, If either anti-virus or OS-syst then run into bad sectors, weird things can again happen. The reason for this is that the chain HDD-COntroller-OS typically cant speak properly with each other, decode the error codes produced by HDD firmware, controller,low level drivers and finally stoopid Windows GUI.

But then another journalist will again claim that NSA deletes her files at nights, and that she heard NSA clicking on internet


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