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About CHKDSK

Chkdsk is a Microsoft utility which checks your computer's hard drives for any cross-linked files, mis-stated free space, bad file table entries, bad sectors on the disk surface, or any additional errors with the hard disk drive.

When something bad happens to a Windows 2000 or XP computer, and it has to be shut down by pressing the power button - or by pulling the AC plug, or it crashes to a BSOD (Blue Screen of Death), or suffers a power outage while operating, the operating system will set a "flag" indicating that the drive/partition/volume is "dirty" and will attempt to check it on reboot, by running chkdsk.

You can manually check the state of the dirty flag for your C: drive, using an account with Administrator level privileges. To do this open a Command Windows (Start > Run > type: CMD), and at the Command Prompt type: fsutil dirty query c:

Shortcut to run Chkdsk:

For Windows 2000/XP, double-click on the icon "My Computer". Right-click on the drive icon representing the hard disk or partition you want to check. Select Properties from the flyout menu. Click the Tools tab at the top. From there you can run Chkdsk ("Error-checking"), as well as File/Folder Backups and Defragmenter.

Note that Windows 2000 and XP ( and NT) computers will need to reboot to allow Chkdsk to run on the boot disk/system partitions during the startup sequence. These volumes cannot be checked or fixed while Windows is running.

Windows NT/2000/XP Chkdsk usage and options:

To run chkdsk on a fixed disk, you must be a member of the Administrators group.

If you want chkdsk to correct disk errors, you cannot have open files on the drive. If files are open, the following error message appears:

Chkdsk cannot run because the volume is in use by another process. Would you like to schedule this volume to be checked the next time the system restarts? (Y/N)

If you choose to check the drive the next time you restart the computer, chkdsk checks the drive and corrects errors automatically when you restart the computer. If the drive partition is a boot partition, chkdsk automatically restarts the computer after it checks the drive.

Chkdsk examines disk space and disk use for the file allocation table (FAT) and NTFS file systems. Chkdsk provides information specific to each file system in a status report. The status report shows errors found in the file system. If you run chkdsk without the /f command-line option on an active partition, it might report spurious errors because it cannot lock the drive. You should use chkdsk occasionally on each disk to check for errors. Chkdsk corrects disk errors only if you specify the /f command-line option.


Chkdsk Command line options:

The following chkdsk commands can be run from a Command Window, at the prompt:

CHKDSK [volume[[path]filename]]] [/F] [/V] [/R] [/X] [/I] [/C] [/L[:size]]

From Windows 7 onward, the following additional switches are available: [/B] [/scan] [spotfix]

volume Specifies the drive letter (followed by a colon), mount point, or volume name.

filename FAT only: Specifies the files to check for fragmentation.

/F Fixes errors on the disk.

/V On FAT/FAT32: Displays the full path and name of every file on the disk. On NTFS: Displays cleanup messages if any.

/R Locates bad sectors and recovers readable information (implies /F).

/L:size NTFS only: Changes the log file size to the specified number of kilobytes. If size is not specified, displays current size.

/X Forces the volume to dismount first if necessary. All opened handles to the volume would then be invalid (implies /F).

/I NTFS only: Performs a less vigorous check of index entries.

/C NTFS only: Skips checking of cycles within the folder structure.

/B NTFS only, in Windows 7 and newer: Re-evaluates bad clusters on the volume (implies /R)

/scan NTFS only, in Windows 7 and newer: Runs an online scan on the volume

/spotfix NTFS only, in Windows 7 and newer: Runs "spotfixing" on the volume

/? Displays help at the command prompt. Use this switch to reveal all of the possible switches for your version of Windows.

The /I or /C switch reduces the amount of time required to run Chkdsk by skipping certain checks of the volume.

You can read about all available Chkdsk options and their usage on this Microsoft page.


Recovery Console Chkdsk Options

Capital letters are used below for emphasis, but are not required.

If you have installed the Windows Recovery Console, or have your Windows XP CD handy, you can boot into/from it, logon to your C: drive, then run chkdsk manually.

There are three options available when running chkdsk from the Recovery Console:

  1. CHKDSK (drive:) - checks (optional drive letter) for errors and reports if any are found, but makes no changes
  2. CHKDSK (drive:) /P - Checks for and fixes any file system errors it finds
  3. CHKDSK (drive:) /R - Performs error checking above, plus scans the entire disk for bad sectors and tries to recover data from them and move it to good sectors.
  4. The (drive:) above is optional, and is only needed to specify checking a different drive letter than the one you have logged onto. If you are only checking your C drive leave that letter out.

Examples:

  1. CHKDSK /P - will check your boot (C) drive for errors and fix them, but won't do a surface scan
  2. CHKDSK D: /R - checks for and fixes errors on hard drive or partition D:, and performs a full surface scan/repair.

More information is available for installing and using the command line Recovery Console, here.

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