I have a hard drive with 3 bad sectors. I know the sector numbers and the computer can still boot into Windows. I want to run sector repair from an HDD diagnostics tool from the manufacturer, but before I do that, I'd like to know what files are affected. Is there a way to figure out what file or files are occupying those sectors?


8 Answers 8


Try nfi.exe - Windows NT File System (NTFS) File Sector Information Utility. Download from Microsoft OEM Support Tools Phase 3 SR2.

> nfi.exe
Dumps information about an NTFS volume, and optionally determines
which volume and file contains a particular sector.

Usage: nfi drive-letter [logical-sector-number]

        Drive-letter can be a single character or a character followed
        by a colon (i.e., C or C: are acceptable).

        Logical-sector-number is a decimal or 0x-prefixed hex
        number, specifying a sector number relative to the volume
        whose drive letter is given by drive-letter. If not
        specified, then information about every file on the volume
        is dumped.

   nfi NT-device-path physical-sector-number

        Determines which volume a given physical sector on a drive is
        within, and then which file on the volume it is in.

        NT-device-path is the NT-style path to a physical device.
        It must not include a partition specification.

        Physical-sector-number is a decimal or 0x-prefixed hex
        number, specifying a sector number relative to the physical
        drive whose device path is given by NT-device-path.

    nfi full-win32-path

        Dumps information about a particular file. full-win32-path
        must start with a drive letter and a colon.

Note you must omit the "\?" prefix of the block device path. Example:

C:\Users\admin\Downloads>nfi \Device\Harddisk0\DR0 28521816
NTFS File Sector Information Utility.
Copyright (C) Microsoft Corporation 1999. All rights reserved.

***Physical sector 28521816 (0x1b33558) is in file number 5766 on drive C.
    $DATA (nonresident)
        physical sectors 32863720-34098663 (0x1f575e8-0x2084de7)
        physical sectors 28519912-32863719 (0x1b32de8-0x1f575e7)
        physical sectors 25727944-26291143 (0x18893c8-0x1912bc7)
        physical sectors 95163976-115106143 (0x5ac1648-0x6dc615f)
  • If you don't know NT-device-path, you can try to find it with dd --list. (Attention to users with Unix tools in PATH: the dd here is C:\WINDOWS\system32\dd.exe, you may need to use the full path)
    – user
    Commented Jan 18, 2016 at 9:27
  • Windows 10 doesn't have this utility in system32. c:\Windows\System32>dd.exe 'dd.exe' is not recognized as an internal or external command, operable program or batch file.
    – Aen Sidhe
    Commented Jul 17, 2016 at 6:51
  • Oh, sorry, it isn't a system tool, it's from here: chrysocome.net/dd (@Aen, thanks for reporting)
    – user
    Commented Dec 25, 2016 at 18:24
  • 1
    The download link on microsoft site is dead
    – basin
    Commented Jun 10, 2017 at 7:00
  • 4
    Can also be found on the wayback machine web.archive.org/web/20150329185738/http://…
    – mkey
    Commented Dec 28, 2017 at 13:37

Here's the process using WinHex, a handy hex editor that can examine and edit drives directly. Be very careful; this tool can damage your system if used inappropriately. Open disks read-only whenever possible.

  1. Since you have the bad sector locations already, you can open the drive in WinHex directly ("Open Disk" toolbar button) and then navigate to the sector to view the data ("Go to Sector" toolbar button). Assuming your sector locations are physical sector addresses, you need to open your physical drive in this step.

    This won't identify the file directly, but the left-hand pane should identify the partition that contains this sector and its corresponding relative sector address.

  2. If the partition you've identified is an NTFS or FAT partition, we can open the partition directly ("Open Disk" again). This will open the partition in a new tab, so you can switch back and forth as needed. In the partition tab, use the "Go to Sector" function again, but this time input the translated sector (the "relative sector" identified in the drive view).

    Now, in the left-hand pane, you should see a section on "Alloc. of visible drive space". Under this is the cluster #, physical sector #, logical (relative) sector #, and the filename if this sector actually belongs to a file.

If these steps don't give you an immediate answer, your bad sectors may not be in use. If the results are unclear, you may have to do some more digging to find your answer.

  • 1
    the downloadable version claims to be an evaluation version, but seems very capable. i'm not sure what the trial period is. see here for license options: x-ways.net/winhex/order.html Commented Jan 21, 2010 at 7:49
  • WinHex was the bomb....Found what files where affected by the bad sectors (absolute sectors from surface scan) in minutes. Awesome tutorial. Thanks I would vote u up "quack quixote" but I don't have the 15 reputation necessary......
    – user102373
    Commented Oct 21, 2011 at 6:03
  • Can the user interface be coerced into revealing this information without reading the sector? I am performing recovery on a disk that shuts down (detaches and powers off) when I read particular sectors.
    – sheldonh
    Commented Dec 16, 2014 at 19:29
  • winhex website appears down/unavailable (i.imgur.com/1FAX5cN.png) try the nfi solution below. straight and simple. free. "immediate answer" ;) Commented Sep 25, 2015 at 13:11

You may use fsutil from Administrator command prompt. Subcommand volume has querycluster subsubcommand. See Windows Command-line Reference Fsutil.

Fsutil takes cluster number in Logical drive as input argument, instead of sector number. But it should be easy to calculate this number:
cluster# = (absolute_sector - start_of_partition_sector) / sectors_per_cluster.

Example output:

c:\tmp> fsutil volume querycluster C: 5235
Cluster 0x0000000000001473, verwendet von
 ----D \Program Filesx86)\LibreOffice 4\program\fwilo.dll::$DATA

Most defragmenting programs show a disk-map displaying all the clusters on the disk which you can then click (look for the ones marked as bad) to view the file(s) located in that cluster.

As Walter said, any disk and OS combo from the past decade or so will make sure to relocate files from bad sectors automatically (drive firmware usually handles this, but disk tools like chkdsk or defragmenters will usually do this as well).


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  • Looks promising, I'll give it a go.
    – ChrisWue
    Commented Jan 25, 2012 at 21:13

DiskView from Sysinternals performs exactly this function: to display a diskmap of the drive and let you see what files occupy what clusters.

Unfortunately, there does not seem to be a way of displaying the names of system files.

DiskView main window DiskView system file

  • It only works with NTFS partitions
    – eadmaster
    Commented Dec 5, 2013 at 5:08
  • That’s why I posted it as a separate answer, because it is a tool made specifically for this purpose, so it answers the question, but it is limited (I still use FAT32 extensively), so it is not the be-all-end-all solution. (Yet?)
    – Synetech
    Commented Dec 5, 2013 at 6:09

I know thread is old but for the record for everyone having such issue there is way to check it from linux. One can always use some live linux on cd/usb stick, like slax which is super easy to run. Anyway, back to business.

I had found today some smartd deamon logs with unreadable sectors warnings and decided to investigate that. After research I eventually run (# is prompt indicating root privileges, sudo can be used instead if one is running as ordinary user):

# smartctl -H /dev/sda2

SMART overall-health self-assessment test result: PASSED

Which indicates that that drive is somewhat healthy, which is good. But I followed and investigated further and run badblocks.

# badblocks -v /dev/sda2 > ~/log/sda2.badsectors
# cat ~/log/sda2.badsectors


So there was some badblock which I wanted to know which file it belongs to and found that it could be done with debugfs, the problem was that my partition was ntfs so I used ntfstools which is the key:

# ntfscluster -s 271521948 /dev/sda2 > 271521948.secinfo 2>&1
# cat 271521948.secinfo | grep -v "extent"

Searching for sector 271521948
Inode 142427 /tmp/dl/setup_torch_2.exe/$DATA
* one inode found

/ grep -v "extent" is to get rid off lot of useless information displayed by ntfscluster /

So in case of ntfs all one needs is ntfscluster -s $SECTOR.


RunTime's DiskExplorer allows you to examine a drive by sector. It's payware ($70 for the NTFS version) but free to try. They have versions for NTFS, FAT and Linux (ext2/3).

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  • This looked promising, but sadly it doesn't work. DiskExplorer displays "Invalid MFT entry" for every sector of the drive.
    – Jason81
    Commented Jan 20, 2010 at 1:26
  • i expect there's a configuration step you're missing if it shows that for all sectors, but i haven't used this tool in a long time so i can't give you direct instructions with it. i'll add another answer with a separate tool; perhaps someone else will chime in with proper usage of this one. Commented Jan 21, 2010 at 7:41
  • It’s not a configuration problem, it’s that Disk Explorer is just very complicated and hard to use. It is not automatic enough. (The old DOS program Norton Disk Doctor was similar, but much easier to use because it automatically read and adjusted to file-system structures. Shame it didn’t support NTFS and was discontinued.)
    – Synetech
    Commented Dec 5, 2013 at 6:11

as far as i know when a drive hits a certain number of read errors on a sector it gets marked as bad and its contents are copied away to another place on the drive. this usually happens before the data on that sector has become completely unreadable.

I try to dig up a source for that, just read it yesterday but cannot remember where.

from man hdparm (8)

Note also that the --repair-sector flag can be used to restore (any) bad sectors when they are no longer needed, including sectors that were genuinely bad (the drive will likely remap those to a fresh area on the media).

Bottom line: you don't have to care about bad sectors, the harddrives firmware does that for you. only thing you have to do is get a new drive before there are too many of them and your drive dies.

  • I'm pretty sure that reallocation happens on write and not on read. The SMART data of the drive seems confirms that. The number of pending sectors is high (larger than 0) while the Sector Reallocation Count is 0. For me that means: There are bad sectors marked for reallocation but they have not yet been reallocated.
    – ChrisWue
    Commented Jan 25, 2012 at 20:54
  • have you tried CHKDSK? en.wikipedia.org/wiki/CHKDSK
    – Baarn
    Commented Jan 25, 2012 at 21:01
  • look at the /r option
    – Baarn
    Commented Jan 25, 2012 at 21:02
  • getting info out about the files stored in that sector seems to be not possible though.
    – Baarn
    Commented Jan 25, 2012 at 21:05

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