Windows 7 consists of a “self healing NTFS” file system". By the way NTFS simply means “New Technology File System, which being hardly new at all, has been refined and revamped over the years to better diagnose and repair both logical and hardware based disk errors and problems. The “self healing” portion of the file system simply means that Windows is constantly monitoring the hard disk for errors and problems while the operating system is running. This process takes place in the background without any user interaction required. The automated process is not perfect and if you suspect your hard drive to be running erroneously, Microsoft has included several command line and GUI based utilities to help diagnose and resolve these issues manually. The Windows CHKDSK (check disk) utility can be used to identify bas sectors, clusters, file directory errors, problems with cross linked files, and in some cases recover corrupted data from bad areas of a corrupt drive and move that data to a working portion of the drive.
Running CHKDSK from the Windows GUI:
You can run the CHKDSK utility from the Windows GUI by clicking start, clicking computer, and right clicking the drive you want to check, then click properties, tools, and check now. You will be presented with the options to “automatically fix file system errors”, and “sna for and attempt recovery of bad sectors.” If you suspect issue with your drive, you should back up all your data first, then select both options and click start. The CHKDSK utility requires that drive not be in use and no system files are open in order to process the request. You may be presented with a message that states, “The volume is in use by another process. Would you like to schedule this volume to be checked the next time the system restarts?” This message is stated because the volume you are checking is required to be “locked” by the CHKDSK utility in order for any recovery of corrupted data to be performed. Select yes, and when you reboot your PC the disk checking utility will run. It may take some time for this process to complete depending on the size of the volume in Gigabytes that you are analyzing. Larger volumes such 500GB can take a considerable amount of time to finish.
You can also use the command line utility to check for errors on a given disk:
Launch the command line interface in Windows 7 with administrator privileges by clicking start, all programs, and right clicking the command utility and selecting “run as administrator.” Now select the disk to want to check. If it’s your main operating system partition you are checking then select the C:\ drive by typing “CD C:\” without the quotes to switch to your C drive, or “CD” again without the quotes and selecting the corresponding drive you want to check for errors. Now type C: /f /r. Check disk will now scan the drive for both logical operating system and logical errors related to the given file system, and attempt to recover data from any bad sectors by moving that data to working sectors on the current volume. The “F” parameter instructs to repair common logical system errors related to the file system in general, and the “R” parameter checks for and attempts the recovery of any bad sectors on the volume.
If you suspect a larger number of bad sectors on a given volume you can run the “CHKDSK /b” command on that volume to attempt to recover lost disk space as a result of many bad clusters.
In some cases Windows 7 may schedule the disk checking utility run automatically if it detects errors during normal operation. You can also schedule the disk checking utility to run the next time the system reboots by typing “chkntfs c” at the Windows command prompt.
The check disk utility first starts by checking and verifying file records within the volumes master boot record. The file record segments in the MFT uniquely identify all files and directories stored within the NTFS file system itself.
The check disk utility then checks all directories on the volume. At this point every file and directory stored on the volume, in this case most likely C:, are compared against their file record segments within the master boot record file itself. The more files and directories stored on a given volume, the longer this stage of the error checking process will take.
At this point CHKDSK verifies security descriptors for the given volume. Once the analysis of security descriptors has completed, a verification of overall file data is performed. This is where the system attempts the recovery of data from bad sectors if any were found on the volume.