UPDATE: It was a bad SATA cable.

I ran the chkdsk /R command on an external WD 1TB hardrive connected via SATA. Here is the output log from chkdsk from event viewer. Not sure what the error message means?

Chkdsk was executed in read/write mode.

Checking file system on E: The type of the file system is NTFS. Volume label is Backup Drive.

CHKDSK is verifying files (stage 1 of 5)... 768 file records processed. File verification completed. 0 large file records processed.
0 bad file records processed. 0 EA records processed. 0 reparse records processed.
CHKDSK is verifying indexes (stage 2 of 5)... 884 index entries processed. Index verification completed. 0 unindexed files scanned.
0 unindexed files recovered.
CHKDSK is verifying security descriptors (stage 3 of 5)... 768 file SDs/SIDs processed. Cleaning up 6 unused index entries from index $SII of file 0x9. Cleaning up 6 unused index entries from index $SDH of file 0x9. Cleaning up 6 unused security descriptors. Security descriptor verification completed. 58 data files processed.
CHKDSK is verifying file data (stage 4 of 5)... 752 files processed. File data verification completed. CHKDSK is verifying free space (stage 5 of 5)... 196108954 free clusters processed.
Free space verification is complete. Read failure with status 0xc000009d at offset 0xb62f1000 for 0x10000 bytes. Read failure with status 0xc000009d at offset 0xb62f1000 for 0x1000 bytes. An unspecified error occurred (6c6f6766696c652e 29c).

  • 1
    nice to hear that a new cable fixed it. Accept my answer to "close" the question. – magicandre1981 Jan 31 '15 at 15:24


Looks like Windows lost the connection to the drive. Replace the cable and check you still have the issue.

  • When chkdsk was finished and I clicked on the device in Windows Explorer it showed it was not connected. It might be a cable issue. – steve Jan 29 '15 at 19:36

Ouch. It looks like you're in trouble.

I suppose that a "read error" could be caused by a bad filesystem: if the filesystem is pointing to some data that isn't successfully readable, then Chkdsk might be trying to do something wrong and stupid based on the instructions it is reading from the incorrect volume. In that case, fully wiping the disk would result in (losing all of your data, but then giving you) a physically functional disk, since software was the issue.

However, such a "Read failure" looks more like a hardware issue. And, in that case, you may be looking at a more unpleasant scenario: a physically bad part that cannot just be fixed by software.

I will try to explain, further, about just what I think is happening here. A lot of people think that Chkdsk is designed to fix a disk. Nope. What it does is to try to fix the structure of the filesystem volume.

See, data is stored using a table (like a chart/graph). What Chkdsk basically does is to make sure that everything on the table looks right. It follows cross-references and makes sure everything looks good.

But you're showing "Read failures". That sounds to me like you've got a hardware error. The computer is unable to read data from the hard drive when Chkdsk is trying to get some data. Chkdsk doesn't know quite how to proceed correctly because it isn't getting some data that it critically needs.

Your best solution is to just give up on Chkdsk /R. Chkdsk isn't getting the data that it needs to do its job correctly. So success is not very likely at this point. Even worse: there is a theoretically possible scenario where Chkdsk might get some partial data or wrong data, and Chkdsk might think it knows how to proceed, and start trying really hard to fix a bunch of stuff, and start making changes, and then later realize that it made so many changes that it got itself into worse trouble and will never manage to fix all of the problems (some of which were just created). In that worst-case scenario, Chkdsk may cause substantially more problems with accessing data. Chkdsk can be useful with fixing minor problems. At this point, you're running the risk of encountering bigger problems than what Chkdsk is typically good at resolving.

Focus on backing up whatever data can be salvaged. If this computer is still useful, other than that bad/damaged part, then supply the computer with a replacement disk. The only thing I recommend using this disk for, now, is to be used for attempting to recover the data before the disk breaks any further. Once it's fully backed up, you can try some other interaction with the disk, like running other disk checkers to see if the hardware works okay. For now, I recommend assuming that chances are good that it doesn't. Start by focusing on getting everything useful backed up.

I'm sorry for the bad news.

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