Groups > alt.comp.os.windows-10 > #181714

New reason for Disk Management ("Shrink") not working

From	Paul <nospam@needed.invalid>
Newsgroups	alt.comp.os.windows-10
Subject	New reason for Disk Management ("Shrink") not working
Date	2025-01-25 10:36 -0500
Organization	A noiseless patient Spider
Message-ID	<vn30ds$2sg61$1@dont-email.me> (permalink)

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I was experimenting with a hard drive the other day,
a 4TB one, and making the C: drive really large.
This was to counter a complaint from some software
"insufficient space to..." type error.

So anyway, I could see a green stripe of material about
half way out on the disk. I figured, no problem,
if I want to shrink the disk, that material will move
out of the way for me.

It didn't.

I got an error, that said the material could not be moved,
and it was different than the usual material problem. It was
traceable to $BADCLUS, a cluster marked off by the file
system driver. Apparently, the SMART log reported a
series of "UDMA CRC errors". These are errors on the
packets on the SATA cable, causing the packets to be
retransmitted. That's not a conventional data CRC as such.
Yet, the software decided that this constituted a bad cluster,
so the area on the disk was marked off.

There is a option in CHKDSK, to verify bad clusters, but this
in fact, scans the entire partition again, as if doing a /r .

This would check for errors, and bad clusters.

chkdsk /f /r C: # Fix structural errors, read-scan all clusters to verify they are working
# Mark off new bad clusters. Do not verify any existing bad clusters.

chkdsk /b C: # This seemingly does the same thing, but can turn bad clusters into good clusters.
# If a cluster was "flagged by mistake", this can undo it.

On a large disk, this can take hours to complete (either command).

When the /b run completed, it reported

"Removing 1 clusters from the Bad Clusters File."

and that is what I was hoping would happen on the /b run.

I went back to Disk Management, and I still could not shrink the volume.
It was still reporting there was a problem with the same issue as
previously.

On a hunch, I booted a Windows 7 disk, cabled up the affected drive,
and did a regular CHKDSK on the partition in question. I know at this
point, there is nothing wrong with any clusters, so there is no need to
do an hours-long scan yet again.

chkdsk /f K: # Windows 7 CHKDSK (of the second disk drive affected partition)

and finally, after this, the Shrink menu started working again in
Disk Management. Presumably this is related to Windows 7
correcting $BITMAP-type issues. (W10/W11 don't handle $BITMAP
properly on partitions any more, leaving data at rest in an
indeterminate state.) Windows 7 cares about the $BITMAP, and
fixed it up for me.

Disk is now back to normal again. The shrink completed (2TB partition down
to 200GB) with no trouble at all. When a partition starts small, you make
it huge, then there won't be a problem to make it as small as it was at first.
Except if there is a bad cluster in there (a cluster flagged as bad
while the file system was running).
_________________________________________________
/ \ 4096 byte
X 512 512 512 512 512 512 512 512 X cluster on
\ XXX / OS C: partition
------------------------------------------------

If any sector is bad, the cluster is marked bad.
The "cluster" is a unit of storage in NTFS.

Paul

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Thread

New reason for Disk Management ("Shrink") not working Paul <nospam@needed.invalid> - 2025-01-25 10:36 -0500
  Re: New reason for Disk Management ("Shrink") not working "Alan K." <alan@invalid.com> - 2025-01-25 10:55 -0500
    Re: New reason for Disk Management ("Shrink") not working Paul <nospam@needed.invalid> - 2025-01-25 11:20 -0500
    Re: New reason for Disk Management ("Shrink") not working Jim <noreply@ghyhgtgfrde.com> - 2025-01-26 02:06 +0000
      Re: New reason for Disk Management ("Shrink") not working "Carlos E.R." <robin_listas@es.invalid> - 2025-01-26 03:29 +0100
      Re: New reason for Disk Management ("Shrink") not working Paul <nospam@needed.invalid> - 2025-01-25 23:14 -0500
  Re: New reason for Disk Management ("Shrink") not working "Carlos E.R." <robin_listas@es.invalid> - 2025-01-26 03:31 +0100
    Re: New reason for Disk Management ("Shrink") not working Paul <nospam@needed.invalid> - 2025-01-25 22:06 -0500
      Re: New reason for Disk Management ("Shrink") not working "Carlos E.R." <robin_listas@es.invalid> - 2025-01-26 13:54 +0100

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