|This chapter excerpt from the Windows Vista Resource Kit, by Mitch Tulloch, Tony Northrup and Jerry Honeycutt with the MSWinVista Team, is printed with permission from Microsoft Press, Copyright 2007.
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Windows Vista might also configure Chkdsk to automatically run at startup if it detects problems with a volume. Volumes that Windows Vista determines need to be checked are considered "dirty." To determine whether a volume is considered dirty, run the following command at a command prompt:
For example, to determine whether drive C is considered dirty, run:
You can also use the Chkntfs tool to prevent a dirty volume from being checked at startup, which is useful if you want to avoid the time-consuming Chkdsk and will not be at the computer during startup to bypass Chkdsk. For more information, run the following at a command prompt:
Chkdsk Process on NTFS VolumesWhen you run Chkdsk on NTFS volumes, the Chkdsk process consists of three major stages and two optional stages. Chkdsk displays its progress for each stage with the following messages:
Windows is verifying files (stage 1 of 5)... File verification completed. CHKDSK is verifying indexes (stage 2 of 5)... Index verification completed. CHKDSK is verifying security descriptors (stage 3 of 5)... Security descriptor verification completed. CHKDSK is verifying file data (stage 4 of 5)... File data verification completed. CHKDSK is verifying free space (stage 5 of 5)... Free space verification completed.
The following list describes each of the Chkdsk stages.
Stage 1: Chkdsk verifies each file record segment in the master file table During stage 1, Chkdsk examines each file record segment in the volume's master file table (MFT). A specific file record segment in the MFT uniquely identifies every file and directory on an NTFS volume. The percent complete that Chkdsk displays during this phase is the percent of the MFT that has been verified.
The percent complete indicator advances relatively smoothly throughout this phase, although some unevenness might occur. For example, file record segments that are not in use require less time to process than do those that are in use, and larger security descriptors take more time to process than do smaller ones. Overall the percent complete is a fairly accurate representation of the actual time required for that phase.
Stage 2: Chkdsk checks the directories in the volume During stage 2, Chkdsk examines each of the indexes (directories) on the volume for internal consistency and verifies that every file and directory represented by a file record segment in the MFT is referenced by at least one directory. Chkdsk also confirms that every file or subdirectory referenced in each directory actually exists as a valid file record segment in the MFT and checks for circular directory references. Chkdsk then confirms that the time stamps and the file size information associated with files are up-to-date in the directory listings for those files.
The percent complete that Chkdsk displays during this phase is the percent of the total number of files on the volume that are checked. For volumes with many thousands of files and folders, the time required to complete this stage can be significant.
The duration of stage 2 varies because the amount of time required to process a directory is closely tied to the number of files or subdirectories listed in that directory. Because of this dependency, the percent complete indicator might not advance smoothly during stage 2, though the indicator continues to advance even for large directories. Therefore, do not use the percent complete as a reliable representation of the actual time remaining for this phase.
Stage 3: Chkdsk verifies the security descriptors for each volume During stage 3, Chkdsk examines each of the security descriptors associated with each file and directory on the volume by verifying that each security descriptor structure is well formed and internally consistent. The percent complete that Chkdsk displays during this phase is the percent of the number of files and directories on the volume that are checked.
The percent complete indicator advances relatively smoothly throughout this phase, although some unevenness might occur.
Stage 4 (optional): Chkdsk verifies file data During stage 4, Chkdsk verifies all clusters in use. Chkdsk performs stages 4 and 5 if you specify the /r parameter when you run Chkdsk. The /r parameter confirms that the sectors in each cluster are usable. Specifying the /r parameter is usually not necessary because NTFS identifies and remaps bad sectors during the course of normal operations, but you can use the /r parameter if you suspect the disk has bad sectors.
The percent complete that Chkdsk displays during stage 4 is based on the percent of used clusters that are checked. Used clusters typically take longer to check than unused clusters, so stage 4 lasts longer than stage 5 on a volume with equal amounts of used and unused clusters.
For a volume with mostly unused clusters, stage 5 takes longer than stage 4.
Stage 5 (optional): Chkdsk verifies free space During stage 5, Chkdsk verifies unused clusters. Chkdsk performs stage 5 only if you specify the /r parameter when you run Chkdsk. The percent complete that Chkdsk displays during stage 5 is the percent of unused clusters that are checked.
How to Troubleshoot Disk Problems in Microsoft Windows Vista
How to prepare for disk failures
How to use Chkdsk
How to use the graphical Chkdsk interface
How to determine whether Chkdsk is scheduled to run
How to use the Disk Cleanup Wizard
How to disable non-volatile caching
Reprinted with permission from Microsoft Press. From Windows Vista Resource Kit (ISBN:9780735622838) Microsoft Press. All rights reserved.
This was first published in October 2007