Conflicting results from Chkdsk -- Why?

[cranioscopical]

Background:

• This is a system running XP Pro SP3, with NTFS formatted drives
• A few days back I had some trouble with corrupted files on my boot drive. (That was caused, I think, by some tomfoolery with an eSATA drive.)
• The system couldn't even start Windows.
• I reformatted the boot drive and replaced everything from a known good backup.
• The system has been perfectly fine since.

My problem is:

• Yesterday, I thought I'd check to see how things stand. (You know how it is... poke into something in a idle moment, spend the next month wishing you'd left well-enough alone.)
• As a first step, I ran chkdsk on the boot drive from inside Windows (so chkdsk was in read-only mode).
• Chkdsk found an error and would have recovered file xxx to folder yyy etc.
• I set chkdsk to run with '/F' on reboot.
• On boot, Chkdsk ran its '/F' scan on the boot drive and found... nothing wrong.

And the question is...

Can someone tell me why the disparity occurs between results from chkdsk on the two runs?

What next steps would be sensible? (Leave the forum, never to return is not an option  )

Thanks for looking at this!

[Darwin]

Yesterday, I thought I'd check to see how things stand. (You know how it is... poke into something in a idle moment, spend the next month wishing you'd left well-enough alone.)

Oh, how I identify with that!

I've had this happen to me before as well (I'm now on WinXP Pro Sp-3 but at the time was on Sp-2). I concluded that I trust the boot scan over the "read-only" scan done while windows was running. That was at least a year ago and the drive is still fine. FWIW, I've occasionally run CHKDSK from within windows since then and the error isn't there... No, I will NOT run CHKDSK right now to check on this (see your quote, referenced above) 

[f0dder]

Remember that your boot volume has changes all the time - think of how often the registry is modified.

It's quite possible that there's a filesystem change between the time CHKDSK reads some of the disk structures, and before it progresses to some of the deeper checks. So don't be too worried about the discrepancy when checking a volume that can't be locked exclusively.

[cranioscopical]

Thank you, gentlemen.

I shall proceed apace to do nothing 

[Carol Haynes]

This happens all the time on my system - I think it is to do with open files.

If you want to really cheack the file system open a DOS windows and run CHKDSK C: /R /V it will then say you need to dot his a boot time so say yes and reboot.

[f0dder]

<pedantic>Command Prompt, not DOS window </pedantic>

for non-system volumes, you can do a "force dismount" (might mess up some running apps, so be careful!) - then you shouldn't get those discrepancies. But since you can't do that for the system volume, you do need the "run on next reboot".