Checks the file system and file system metadata of a volume for logical and physical errors. If used without parameters, chkdsk displays only the status of the volume and does not fix any errors. If used with the /f, /r, /x, or /b parameters, it fixes errors on the volume.
Syntax
CHKDSK [drive:][[path]filename] [/F] [/V] [/R] [/L[:size]]
Switches
| [drive:] | Specify the drive to check. |
| filename | Specify the file(s) to check for fragmentation (FAT only). |
| /F | Automatically Fix file system errors on the disk. |
| /R | Scan for and attempt Recovery of bad sectors. |
| /V | Display the full path and name of every file on the disk. |
| /L:size | NTFS only: change the log file size to the specified number of kilobytes. If size is not pecified, displays the current log size and the drive type (FAT or NTFS). |
| /C | Skip directory corruption checks. |
| /I | Skip corruption checks that compare directory entries to the file record segment (FRS) in the volume’s master file table (MFT) |
Examples
Fixing Errors
If the drive is the boot partition for NT, you will be prompted to run the check during the next boot. To issue chkdsk on a hard drive you must be a member of the Administrators group. If you specify the /f switch, chkdsk will show an error if open files are found on the disk.
If you use chkdsk /f on a very large disk or a disk with a very large number of files (millions), chkdsk may take a long time to complete. The computer will not be available during this time, as chkdsk does not relinquish control until it is done.
Scanning Only
If a file needs to be fixed chkdsk will alerts you with a message but will not fix the error(s). Chkdsk may report lost allocation units on the disk – it will produce this report even if the files are in-use (open). If corruption is found, consider closing all files and repairing the disk with /F. Often the easiest method (even for non-primary partition drives) is to run the scan during bootup.
Cluster (or block) Size
CHKDSK produces a report that shows the the block /cluster size typically: “4096 bytes in each allocation unit.”
Exit codes
| 0 | No errors were found |
| 1 | Errors were found and fixed |
| 2 | Could not check the disk, did not or could not fix errors |
Notes
It is possible to run CHKDSK on a live system (as long as /f is not specified), a good strategy is to schedule an AT job to detect any disk problems by running CHKDSK >LogFileOfErrors.txt – then check the log files and manually fix any problems only as they occur.
When CHKDSK is set to run at boot-up there is a delay to allow the check to be cancelled – this can be configured in the registry:
HKLM\System\CurrentControlSet\Control\Session Manager
REG_DWORD:AutoChkTimeOutData
The value is the time in seconds that you want CHKDSK to wait (0 = no delay) default is 10 seconds.