Bad Sectors on HD

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  1. Posts : 21,482
    Win 7 x64 Home Premium (and x86 VirtualBox VM)/Win10
       #1

    Bad Sectors on HD


    Packard Bell machine with original HD - ancient beast.
    Owner is unemployed like me, so can't afford a new HD or machine.
    Windows CHKDSK shows 52KB in bad sectors (my usual response - get a new HD)

    Ran SeaTools For DOS - it found the expected 13 bad sectors and offered to repair them, so I said go ahead - said it had fixed them
    Ran Seatools again, passed.

    Back in WIndows, ran CHKDSK /R to clear the Windows bad sector tags - but it still shows 52KB in bad sectors.

    Seatools is running again.
    IF (big if) Seatools gives it the green light, is there any other way to clear the bad sector tags from Windows?
      My Computer


  2. Posts : 6,292
    Windows 7 64 Bit Home Premium SP1
       #2

    Noel, did you try running CHKDSK /f and CHKDSK /b ?
    That should clear the tags.

    Chkdsk
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  3. Posts : 21,482
    Win 7 x64 Home Premium (and x86 VirtualBox VM)/Win10
    Thread Starter
       #3

    /R implies /F and /B :)


    ....or maybe not?
    From that article, it looks like /b implies /r ??

    Whatever, :)
    Last edited by NoelDP; 01 Jul 2012 at 07:41. Reason: I read the article :)
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  4. Posts : 21,482
    Win 7 x64 Home Premium (and x86 VirtualBox VM)/Win10
    Thread Starter
       #4

    .... and I just realised/remembered that the machine is so old, it's XP - which doesn't have a /B option
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  5. Posts : 19,384
    Windows 10 Pro x64 ; Xubuntu x64
       #5

    Noel,

    I stumbled across this a few months ago, and have been meaning to test it, but haven't gotten around to it - a utiltiy to repair bad sectors. So I can't say that this will work, so consider with caution.

    HDAT2/CBL Hard Disk Repair Utility

    Click on the description link.

    Have you examined the disk using a live Linux boot CD? Debian 6 has nifty tools for checking disks.

    UK Mirror Service: sites/cdimage.debian.org/debian-cd

    Regards,
    Golden
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  6. Posts : 6,292
    Windows 7 64 Bit Home Premium SP1
       #6

    In the past I had read that Chkdsk keeps it's 'bad sector list' on a particular HDD forever, or until CHKDSK says they are clear. I would have thought that had changed by now.

    If running chkdsk /f by itself does not clear the list then the only other solution I know about is a true low level format of the disk.
    Hardly seems worth it for a few bad sectors, particularly if Seatools says it is good.
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  7. Posts : 21,482
    Win 7 x64 Home Premium (and x86 VirtualBox VM)/Win10
    Thread Starter
       #7

    Thanks, Golden - the utility you linked to is only for FAT drives, and this is NTFS so it wouldn't work.

    The Windows Bad Sector count is held in the MFT - not on the disk itself - which is why the /B switch works in Vista and Win7.
    The way it works is - I gather, perhaps wrongly.....
    1) Windows has a problem reading a sector (usually an ECC error) so it tells the Disk firmware that there's a problem. The firmware then retries the read.
    2) After so many attempts, Windows gives up, and tags the sector in the MFT as bad, and then instructs the firmware to do the same on the HD.
    3) Along comes the manufacturer's utility, and that can't see any problem with the sector on the physical read, so it unmarks it as a bad sector.
    4) Windows still has the sector marked as bad in the MFT so ignores it totally, and still shows it in a CHKDSK report.


    Note that this only applies to software failure (possibly caused by power spike/drop during read), NOT a hardware fail, such as a dust particle on the disk blocking reads (you can sometimes tell this, if a number of contiguous sectors are failing, and refuse repair by the utility)


    The /B switch in Vista/Win7 clears the MFT table so that the implied /R can retest the sector readability, and /F can retest the data.
    In theory, a simple reformat will clear a software bad sector, providing the firmware sectors have been reset first.

    However - I made the mistake on this machine of not running the CHKDSK until after reinstalling, updating and installing the required programs. I do NOT want to have to do that again in a hurry!
    ...and if I clone the drive, it will clone the problem.
      My Computer


  8. Posts : 21,482
    Win 7 x64 Home Premium (and x86 VirtualBox VM)/Win10
    Thread Starter
       #8

    NoelDP said:
    4) Windows still has the sector marked as bad in the MFT so ignores it totally, and still shows it in a CHKDSK report.

    re-reading that, it makes me wonder if perhaps SeaTools for Windows has the ability to do teh necessary??

    Back soon!
      My Computer


  9. Posts : 6,292
    Windows 7 64 Bit Home Premium SP1
       #9

    That is my understanding also.

    I'm not sure if a simple format will clear the list. I have always used Diskpart Clean All to "low level format" (antiquated term, I know, can't help it!) in these cases with good success.

    I'm not sure that cloning (imaging) a disk will copy bad sectors. Isn't it just raw data that is copied?
      My Computer


  10. Posts : 6,292
    Windows 7 64 Bit Home Premium SP1
       #10

    NoelDP said:
    NoelDP said:
    4) Windows still has the sector marked as bad in the MFT so ignores it totally, and still shows it in a CHKDSK report.

    re-reading that, it makes me wonder if perhaps SeaTools for Windows has the ability to do teh necessary??

    Back soon!
    It would be good to know. Carry on!
      My Computer


 
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