Wizard Prang said:
re: CHKDSK...The discussion below is intended to be ONLY about the possible impact of using CHKDSK...it is not explicitly claiming anything about whether an arbitrary "data recovery program" will or will not be of help
...I have done a little reading. Some (including Microsoft http://support.microsoft.com/kb/315688
) suggest using CHKDSK
, while others say that CHKDSK
will err on the side of caution and "fix" the disk by completely blowing the missing files away....
. And...I'm trying to explain CHKDSK
roughly and broadly here, so a specific scenario may not be covered. (And, because of the dosage of the pain meds I'm on today...the way I say things in this particular post may not make as much sense to others as I think it does.)
Warnings about using CHKDSK
are appropriate, even in "last-ditch" cases where using CHKDSK
is ultimately necessary in order to repair the filesystem structure
(aka "meta-data)...e.g. you haven't implemented strong backup protocols,
will if necessary "sacrifice" the information on how user/system data were originally
inter-connected in the disk, to make the filesystem structure
"bright and shiny new" and ready for the OS to use it again. CHKDSK
is pretty much an "officially sanctioned moron" and doesn't give a damn about user data content
. Unfortunately, this can result in making it virtually impossible to reconstruct your data in a useful/reliable way even using a data recovery program afterwards. Your data may still be "on the disk" afterwards, but with CHKDSK
...much of and possibly all the information that "links" your data together in a meaningful way can/will be lost. Under such conditions, a data recovery program may "recover" much of your raw data, but it can still be up to you to manually
assemble and/or verify a possibly huge part of it so it means something intelligible to you and/or an application...and that's a high-level skill often beyond many users. Among other factors
, the amount of file fragmentation prior to the failure can make a profound difference in how difficult that then becomes and how successful or useful a data recovery program may end up being in a given situation.
some parts are in some degree of order after CHKDSK
, it's pure luck. CHKDSK
is not a very smart program. Something or someone likely still has to reconstruct a file's contents piece by piece based on what it/he believes is the correct sequence. A data recovery program may help with some of the ordering, but because of the way CHKDSK
works, data can still be put in the wrong order or associated with the wrong discrete file. For example, you could end up with something like "Alas poor Yorick! I knew O Romeo. To sleep, perchance to fire burn and cauldron bubble". Even if the file's parts are "connected" so the OS
can read them, the underlying file
structure and/or content can still be mish-mashed (e.g. an .mp3
file with even a single element in it from a .doc
(or other) file(s) may make the mp3 player "choke" on playing the "music" file saying it's an incompatible format or no codec exists to play it. Or an image of a Rembrandt may end up looking more like something by Picasso).
So even if a particular file is "recovered" to 99.999% of the original content and structure, it can remain unusable for all PRACTICAL purposes
Worse yet...in a spreadsheet data file CHKDSK
could change the data sequencing and attempts at file reconstruction could end up interchanging the location of some "cells" (or even put information from another file into some "cells") and your spreadsheet would now UNDETECTABLY
provide you with bad information. The consequence might vary from minor embarrassment in a department meeting to IRS audit/fines/jail time.
On a RELATED
topic, here's some info on data integrity/usability for people who think NTFS (journaled file system) protects your data 100% in the event of a system/OS "crash" or power disruption. It's similar because it is also an issue of preserving the filesystem "structure"/meta-data v. protecting the actual content of files.