[SOLVED] Need help with hard drive with bad clusters recovery and questions

Minaz

Prominent
Sep 20, 2021
114
4
585
I have a 8TB external hard drive that has bad clusters. I realized the problem when CrystalDiskInfo reported that Current Pending Sector Count = 8 and Uncorrectable Sector Count = 8. So I ran chkdsk /v r and during stage 4, I got this message:

====================
Stage 4: Looking for bad clusters in user file data ...
A disk read error occurredc0000483
The disk does not have enough space to replace bad clusters
detected in file 183960 of name \mydirectory\myfilename.ext
1590512 files processed.
File data verification completed.
Phase duration (User file recovery): 7.93 hours.
====================

Chkdsk is still running and is currently in stage 5, which is checking free space which will likely take all day.

I already have a replacement hard drive on the way. However, I have a few important questions:
  1. This hard drive was only maybe 40% full. Why does it say that there is not enough space to replace that bad cluster? Surely the entire hard drive would not be all bad? How would chkdsk even know this considering that it is only in stage 5 that it is checking bad sectors in the free space (which is most of the drive)? Wouldn't it need to check stage 5 first before knowing if there is enough free space to replace the bad cluster?
  2. Similarly, the above is the entire screen output from Stage 4. Does this mean that just this one file was in a bad cluster, or that there were many files in bad clusters but just this one file cannot be recovered, or that chkdsk found this one file in a bad cluster, couldn't recover it, and there maybe others that chkdsk did not report (because it only reports the first one it finds)?
  3. When chkdsk moves a file from a bad cluster to a good one (assuming this is what it did, I have no idea), is the file therefore recovered and useable or is it a broken file with junk contents and probably needs to be replaced?
  4. CrystalDiskMark gave a caution flag from the pending and uncorrectable = 8 counts. Would this drive likely be salvageable for use after a reformat and flagging the bad sectors? I have no idea how high "8" is but I am trying to interpret "caution" as whether it means to throw away the hard drive or just use it for non-critical tasks.
  5. When my replacement drive comes, what is the best way to transfer the data? Straight file copying, using some disk cloning tool, or other option? Is there any way for me to know which files may have been damaged even after the transfer and need to be replaced?
  6. I do have a recent backup of some (but not all) of the files on the hard drive. Is there any chance that the backups are corrupted too since they are very recent, or would I have received some kind of error message if the files were being backed up were located in bad sectors? I used a backup utility (FreeFileSync) if that makes any difference.

    Thank you.
 
Last edited:
Solution
8 pending and uncorrectable sectors is actually 1 physical sector (8 logical 512-byte sectors = 1 x 4096-byte physical sector).

An NTFS cluster typically occupies 8 logical sectors, so it would appear that there a single bad cluster. Therefore, I would be confident that \mydirectory\myfilename.ext is your only bad file.

I don't understand the "not enough space" warning, though. I would have thought that a repair would have involved the $BadClus metafile.

I would recover your good data to another drive. I would then use a disc editor (eg DMDE freeware) to recover the bad file, including the bad sector. Then I would zero in on the bad sector with DMDE and keep thrashing it until you get a good read ... hopefully.

https://dmde.com/
8 pending and uncorrectable sectors is actually 1 physical sector (8 logical 512-byte sectors = 1 x 4096-byte physical sector).

An NTFS cluster typically occupies 8 logical sectors, so it would appear that there a single bad cluster. Therefore, I would be confident that \mydirectory\myfilename.ext is your only bad file.

I don't understand the "not enough space" warning, though. I would have thought that a repair would have involved the $BadClus metafile.

I would recover your good data to another drive. I would then use a disc editor (eg DMDE freeware) to recover the bad file, including the bad sector. Then I would zero in on the bad sector with DMDE and keep thrashing it until you get a good read ... hopefully.

https://dmde.com/
 
Last edited:
  • Like
Reactions: Minaz
Solution
A hard drive will set aside some space to recover damaged blocks.
This space would be addressable via hardware only.
The maker of the hard drive will have hardware specific test and recovery apps.
Seatools for seagate and data lifeguard for WD.
 
If the damaged file is backed up elsewhere, then simply delete it. This will make its damaged cluster available in the free space. When the OS writes a new file to this cluster, the drive will retest the physical sector and replace it with a spare if bad, or return it to service if good. If bad, the Reallocated Sector Count will be incremented in the SMART report.
 

Minaz

Prominent
Sep 20, 2021
114
4
585
A hard drive will set aside some space to recover damaged blocks.
This space would be addressable via hardware only.
The maker of the hard drive will have hardware specific test and recovery apps.
Seatools for seagate and data lifeguard for WD.
I do understand this now, but I am befuddled that if the reserved area for recovering bad sectors is full, there is no option to use free space on the drive. I mean, I would much rather use up some empty space than to lose data.

I tried using SeaTool, each time a Seagate drive fails, I am optimistic that it would work, but it never does for me. This time, the self diagnosis and short test (both options) aborted before completion, leaving no information. Disabling USB power save did not resolve. I have attempted to use this software in the past and this has always been the case for me, that either the software hard crashes or somehow or other bugs out. Maybe its just me, but I just can't get it to work.
 

Minaz

Prominent
Sep 20, 2021
114
4
585
If the damaged file is backed up elsewhere, then simply delete it. This will make its damaged cluster available in the free space. When the OS writes a new file to this cluster, the drive will retest the physical sector and replace it with a spare if bad, or return it to service if good. If bad, the Reallocated Sector Count will be incremented in the SMART report.

This is what I did, and interestingly the file was automatically regenerated (this was a data file used by an application), so it even saved me the trouble of having to copy it from backup.
 

Minaz

Prominent
Sep 20, 2021
114
4
585
8 pending and uncorrectable sectors is actually 1 physical sector (8 logical 512-byte sectors = 1 x 4096-byte physical sector).

An NTFS cluster typically occupies 8 logical sectors, so it would appear that there a single bad cluster. Therefore, I would be confident that \mydirectory\myfilename.ext is your only bad file.

I don't understand the "not enough space" warning, though. I would have thought that a repair would have involved the $BadClus metafile.

I would recover your good data to another drive. I would then use a disc editor (eg DMDE freeware) to recover the bad file, including the bad sector. Then I would zero in on the bad sector with DMDE and keep thrashing it until you get a good read ... hopefully.

https://dmde.com/
So now that the entire situation has been resolved, I wanted to let you know you were 100% right on the money. There was one single bad file on that one physical bad sector.

Since all the data has been recovered and moved onto a new hard drive, I am now in the process of re-formatting the drive.

SMART (CrystalDiskInfo) still reports 8/8 as before, no change. As mentioned no other files were corrupted and CHKDSK /f /r reported no other errors.

The question now is, I have a spare 8TB HDD. Do you think that this drive is salvageable and can still be used? It is a relatively new drive (less than a year old).

C:\Windows\System32>chkdsk z: /v /r
The type of the file system is NTFS.

Chkdsk cannot run because the volume is in use by another
process. Chkdsk may run if this volume is dismounted first.
ALL OPENED HANDLES TO THIS VOLUME WOULD THEN BE INVALID.
Would you like to force a dismount on this volume? (Y/N) y
Volume dismounted. All opened handles to this volume are now invalid.
Volume label is Games.

Stage 1: Examining basic file system structure ...
1590528 file records processed.
File verification completed.
Phase duration (File record verification): 34.75 seconds.
353 large file records processed.
Phase duration (Orphan file record recovery): 0.43 milliseconds.
0 bad file records processed.
Phase duration (Bad file record checking): 0.21 milliseconds.

Stage 2: Examining file name linkage ...
429 reparse records processed.
1771728 index entries processed.
Index verification completed.
Phase duration (Index verification): 2.79 minutes.
0 unindexed files scanned.
Phase duration (Orphan reconnection): 1.53 seconds.
0 unindexed files recovered to lost and found.
Phase duration (Orphan recovery to lost and found): 2.77 milliseconds.
429 reparse records processed.
Phase duration (Reparse point and Object ID verification): 10.23 milliseconds.

Stage 3: Examining security descriptors ...
Cleaning up 8 unused index entries from index $SII of file 9.
Cleaning up 8 unused index entries from index $SDH of file 9.
Cleaning up 8 unused security descriptors.
Security descriptor verification completed.
Phase duration (Security descriptor verification): 22.99 milliseconds.
90601 data files processed.
Phase duration (Data attribute verification): 0.23 milliseconds.
CHKDSK is verifying Usn Journal...
35414896 USN bytes processed.
Usn Journal verification completed.
Phase duration (USN journal verification): 384.98 milliseconds.

Stage 4: Looking for bad clusters in user file data ...
A disk read error occurredc0000483
The disk does not have enough space to replace bad clusters
detected in file 183960 of name \mydirectory\myfile.ext.
1590512 files processed.
File data verification completed.
Phase duration (User file recovery): 7.93 hours.

Stage 5: Looking for bad, free clusters ...
892647026 free clusters processed.
Free space verification is complete.
Phase duration (Free space recovery): 8.58 hours.

Windows has scanned the file system and found no problems.
No further action is required.

7630683 MB total disk space.
4141386 MB in 1499259 files.
522044 KB in 90602 indexes.
0 KB in bad sectors.
1930147 KB in use by the system.
65536 KB occupied by the log file.
3486902 MB available on disk.

4096 bytes in each allocation unit.
1953455103 total allocation units on disk.
892647026 allocation units available on disk.
Total duration: 16.56 hours (59650157 ms).