Unless you specifically tell scandisk to check the disk surface,
it only checks FAT and makes sure that all the appropriate
clusters can be chained together to "create" each file.  It does
not check to make sure that the storage media (or the contents
of the file) are good.  You must turn on the THOROUGH option
to test the integrity of the drive's platters.

Defrag, on the other hand, actually moves the files around.
Most likely, it moved a chunk of files into a bad section of
your hard disk and then could not recover from it.

Defrag did not cause your problems.  Bad sectors on
the hard drive did.

Even if you had not run defrag, EVENTUALLY your
system would have attempted to write data to the bad
area of your drive and then would have subsequently
crashed when it tried to retrieve that data.

I advise all my customers to run the "normal" scandisk
weekly, and run the thorough mode monthly.

Jim Meagher

----- Original Message -----
From: "John H. Lever" <[log in to unmask]>


> ___________________________________________________________
>
> On Tue, 2 Jan 2001 13:47:52 EST,
> [log in to unmask] wrote:
>
> >With the millions of Windows users who regularly defrag their HD, it is
very
> >unlikly that the utility was the cause of your problem. More likely a
> >hardware or configuration change, a dying hard disk, controller, etc.
would
> >cause this type of situation. Maybe some others can jump in here with
> >opinions, but I would not want readers to think routinly using defrag has
> >"any" chance of creating a problem.
>
>      Coincidentally, the following happened to me on New Year's Eve:-
>
>           I thought I'd run my weekly Scandisk and Defrag.
>           Scandisk reported no problems, Defrag chugged on and on.
>           THEN! Defrag said there was a problem on the disk and I
>           should run Scandisk. Eh?!? I did - and Scandisk just seemed
>           to get to one point and stop.
>
>           As I often do when things look wobbly on the 'puter, I
>           closed it down and re-booted. Error box comes up
>           before Windows starts and says Windows can't read drive C -
>           Abort/Retry/Cancel.
>
>           I hit cancel and got into Windows although little seemed to
>           work after that. Scandisk did! I put Scandisk onto manual
>           and watched it stop, falter, report a fault and ask if I
>           wanted an attempted repair, make the repair, move on to the
>           next cluster and.... repeat the cycle. My conclusion was
>           Scandisk was trying (in fact possibly succeeding) in making
>           the repairs but they took so long it looked like the
>           programme had seized. I cancelled it all out, started it
>           again and opted for all automatic. After 6 hours! Scandisk
>           completed its task.
>
>           I ran Scandisk again, this time in DOS mode (which
>           gives you some different graphics and a little more
>           information) and I now have 5 'bad clusters', but the
>           machine seems to run. I also have 684,032 bytes in bad
>           sectors but regular running of Scandisk seems to indicate
>           these aren't increasing.
>
>           When I originally ran Scandisk and Defrag, I closed
>           EVERYTHING down except Explorer and Systray. I have run
>           Defrag since and it went OK.
>
>      Just my two cents worth, but Defrag now has me running scared.

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