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General discussion

Question on how Chkdsk repairs harddrive

Sep 13, 2007 2:20AM PDT

Recently because of serious system instability, I ran chkdsk to see if the problem was related to bad clusters. Of course Chkdsk found a string of errors, reporting things such as "deleting corrupt attribute record...", "deleting index entry...", and so on. After a long wait, the system rebooted, but I found my system even more unstable. Later I found out through the Event Viewer that Chkdsk did 'something' to numerous files in attempt to repair them. Among those were Windows core system dll's. When I tried to look for those files, they did not exist anywhere on the hard drive.

I am afraid that maybe Chkdsk didn't do a good job repairing the flies. Perhaps what Chkdsk did was just overwriting the bad sectors? I thought at least Chkdsk could move the file segments on that specific sector to another healthy sector to maintain file integrity. I dare not to use Chkdsk again in the future, lest it should delete files by accident, rendering software, personal data, or even Windows useless.

My question is: should I expect Chkdsk to repair the hard drive while also maintaining data integrity? Or is there any other way to do exactly the tasks mentioned above?

Discussion is locked

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Nothing more than directory checks, etc.
Sep 13, 2007 4:22AM PDT

I'm going to decline writing what CHKDSK does and note it won't repair damaged files or a damages OS. For that the tools vary with the OS. Sometimes it's SFC /SCANNOW and for other OSes it's something else.

With all the malware out there, CHKDSK is only a minor tool in the kit.

Bob

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CHKDSK
Sep 14, 2007 4:42PM PDT

Did you run just chkdsk, or did you use chkdsk /f/r? Chkdsk by itself will only check the disk, with /f or /r, or both will move the info to good sectors. Depending on the size of disk it may take awhile. Also it may only happen on a reboot cause it needs exclusive rights to the drive. SFC command will take you to original values, you will need to go to Microsoft update after the sfc was run. Hope this helps.

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clarifications
Sep 15, 2007 2:08AM PDT

Well, I manually made CHKDSK to run at bootup so that it can have so-called "exclusive access" to the harddrive.

My OS was not damaged before I ran CHKDSK; it was just unstable (which I later found out to be nTune's fault). But AFTER I ran CHKDSK, some core system files were gone, such as msxml3r.dll, etc. And these files were all reported as "located in bad sector and was repaired" in CHKDSK's log. Even SFC /scannow did not totally recover them. I had to copy the dll's from my original XP cd.

What I want to know is whether it's normal to lose data while disk utilities, such as CHKDSK, are doing their job?

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Sadly normal.
Sep 15, 2007 2:18AM PDT

It's all about backup. But let's tackle MSXML3 since last week I ran into that and it was annoying that REGSVR32 MSXML3.DLL fails but if you download MSXML3.MSI and install that then all is well. Go figure why.

Here's the MSXML3.MSI I used to correct this one.

Bob

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sigh
Sep 16, 2007 12:26AM PDT

Well then I guess it's prime time for me to make a backup of my drive. It seems that I can't totally rely on CHKDSK. Hopefully the bad sectors won't spread any faster.

Thanks.

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Try System File Checker
Sep 15, 2007 3:49AM PDT

It might be worth trying 'system file checker'. You will need your XP CD handy (or if on your harddrive as a partition it will find any files itself)

Click Start > Run > type CMD press ok. This will bring up a Command Prompt

Type in: SFC /scannow (make sure you have a space after SFC)

Hopefully this should repair or replace any corrupt or missing system files.

Tigger

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re: chkdsk
Sep 16, 2007 3:22AM PDT

CHKDSK is a little boy sent out to do a big man's job.

There are several utilities that 'claim' to do this job, but only 1 that I know really does the job.
SPINRITE from Steve Gibson http://www.grc.com

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Re: chkdsk
Sep 18, 2007 12:05AM PDT

> CHKDSK is a little boy sent out to do a big man's job.

Actually, it's an old man. It's been around since the boot-from-floppy days.

Someone mentioned the need to do a backup. I do this twice a year (should do it more often) and my irreplaceable files, such as the pictures I've taken, are additionaly backed up onto a dvd and far away in my brother's safe.

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re: chkdsk
Sep 19, 2007 5:35AM PDT

Yes, It's old but it's been updated for NTFS.

And backups are nice but they can be nothing if you get bad copies.

I've had this happen with floppies, tapes, cds and dvds.

I make 2 or 3 copies of data files and have not lost data. (YET!!!) But I have had to use all 3 copies to recover data, some files.

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Chkdsk
Sep 19, 2007 9:28AM PDT

well lets start off with the basics. the hard drive is a thin mettallic layer of magnetic material. this magnetic material is divided into clusters, pipes, sectors and all that fun jazz. what chkdsk is checking for is imperfections in this magnetic layer, namely the clusters. when chkdsk finds these errors on the platter (the term for the hard drive) it will attempt to fix these. it will not go through your files and fix them.

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re: chkdsk
Sep 19, 2007 11:55AM PDT

'this magnetic material is divided into clusters, pipes, sectors'

Pipes??? I don't think so!

'what chkdsk is checking for is imperfections in this magnetic layer'

Again I don't think so.

One thing it is looking for is "lost clusters", clusters that are marked as in use but they are not.

Another thing it is looking at is the "indexes".

I could go on but I won't.