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Determine Bad Sectors On A Volume

To determine the number of bad sectors on a volume:

  1. Windows Vista/7 and later

    Open an elevated command prompt.

    Windows NT/2000/XP/2003

    Click Start, choose Run and enter CMD then click OK.

    The command prompt will appear.

  2. Type:


    and press ENTER.

    This activates a volume check in read-only mode (no changes are made). The process may report errors, as per:

    Windows found problems with the file system.
    Run CHKDSK with the /F (fix) option to correct these.

    However, this is normal on a volume which is active, it is not necessarily cause for alarm.

    After performing the check, the statistics will be displayed:

     151681015 KB total disk space.
     147658212 KB in 141079 files.
         74296 KB in 25724 indexes.
            16 KB in bad sectors.
        353815 KB in use by the system.
         65536 KB occupied by the log file.
       3594692 KB available on disk.

          4096 bytes in each allocation unit.
      37920253 total allocation units on disk.
        898673 allocation units available on disk.

  3. Take the number shown next to in bad sectors and multiply by 2. In this example, 16 × 2 = 32 sectors.

    (This calculation is based on a sector size of 512 bytes or ½ kilobyte, which is most normal on modern systems. However, a new disk standard allows for 4096 bytes per physical sector, even though the operating system treats the drive as if having 512 bytes per logical sector. To determine if this is the case, obtain the KB982018 update for Windows 7/2008R2 and run fsutil fsinfo ntfsinfo C:.)

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