Is CHKDSK a data recovery tool?

Check disk otherwise known to Windows users as ‘CHKDSK’ is a hard drive utility which verifies the file system, fixing bad sectors and logical errors. It is useful in that it will report on errors but only make repairs if instructed by the user. However most users do not activate CHKDSK until they have a hard drive problem and by then it’s usually too late. CHKDSK is a great utility to keep your hard drive healthy, but it’s not going to fix a failing disk and will probably exasperate the situation. So when should I use it?

If a user’s file system becomes corrupted, CHKDSK may recover the data, but this is not its primary purpose. Bad sectors are ubiquitous on most hard drives and these don’t necessarily mean your hard drive is not healthy. Options allow the user to automatically fix file system errors and recover data from bad sectors.  However CHKDSK has to run in isolation without any other applications and the user will need to dismount the drive.  This also includes the operating system, hence a user should schedule CHKDSK before closing down the system. On restart CHKDSK will run before loading the operating system and start verifying files. The results of a scheduled CHKDSK can be observed by running the event viewer and clicking <start> then <run> and then entering <eventvwr>.  If you search for ‘Wininit’ under source in the Windows Application Logs, you will see the results.

How does CHKDSK work?
Firstly it checks through all the data listings, making sure that everything is distributed correctly across the hard disk drive. This is a high level scan that simply reads the catalogue. Where the user specifically wants to scan for bad sectors, CHKDSK reads the entire disk – a time consuming process. Where it cannot verify data, it will report an error. But beware, CHKDSK does not know whether the data is correct, simply that it can be read.

When should I run CHKDSK?
Most users run CHKDSK when they suspect an issue, but it is good practise to run this utility routinely to deter problems. CHKDSK is simply a disk utility and is not able to fix mechanical problems inside the hard drive. So if you suspect an imminent failure (such as after the hard drive has been dropped) a user should not put the hard disk drive through the strain of running CHKDSK. Nevertheless if a user is encountering bad sectors and read or write errors, then CHKDSK can isolate those bad sectors. Also if your machine has been crashing, CHKDSK is useful to verify the file system.

Is CHKDSK a data recovery tool?
CHKDSK will not recover lost or damaged files, but can only verify that data is in a consistent and safe state. Where files are damaged, CHKDSK will attempt to separate the damaged files and save the remnants with the file extension.CHK.

Aran Pitter Commercial Manager at Data Recovery Specialists says “Many online forums report CHKDSK causing further problems to file integrity and structures and users should be careful before using it for data recovery purposes. If a user insists on CHKDSK for data recovery, never select automatic repair. This way a user can see what is wrong with the hard drive and take advice before potentially causing more damage to files”.