An external hard drive had trouble mounting after bootup. So I began to clone it using dd.This was quite a while ago, and so I don't recall the exact parameters. Something rather standard for a failing ntfs partitioned drive I'm sure. Anyhow, it failed around a 1/3rd of the way through. And now I have a partial replica of about 350 GB. The external died for good during the dd. I've never been able to get it recognized again.

Is there any way to mount or explore this partially dumped drive?

file -i tells me it is an application/octet-stream; charset=binary

  • if you have a partial image, you can use file carving utilities like photorec to attempt recovery of the files contained entirely within the partial image. unless the filesystem is intact however, the files will loose their name, directory location, etc however, so often the recovered data is almost as useless as the partial image itself. file carving utilities will not work for all types of files, and can only recover files with known binary layouts that have a predictable beginning and end. Nov 13, 2021 at 22:43
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    have you tried ddrescue? if the disk isn;t mechanically dead yet, it may be able to get data off the disk that DD cannot. if you try to use ddrescue be sure to use a log file so you can stop/resume, and change options. generally you want to do a multi-pass approach to using ddrescue. see here: superuser.com/questions/786488/… Now the resulting image will still be damaged if the disk did in fact have unrestoraable blocks, but once you have it on solid hardware, you can use recovery utils on it. Nov 13, 2021 at 23:42
  • As a hail mary, which will reduce the chance of professional recovery, try putting it in the freezer in a ziplock bag overnight. If that fails, as a send-off to its grave try putting it in the oven at a low heat for 10 mins - this has been known to work occassionally as well.
    – davidgo
    Nov 14, 2021 at 1:13
  • I amended my answer to include ddrescue as another possible recovery choice
    – John
    Nov 14, 2021 at 1:37

1 Answer 1


Anyhow, it failed around a 1/3rd of the way through. And now I have a partial replica of about 350 GB.

Your chances from a partial replica are very slim. Data in a file may have pieces in the good part and pieces in the failed part.

A local recovery agency is likely your best choice.

Second choice might be Recuva (cc cleaner) or Spinrite (https://www.grc.com/sr/spinrite.htm)

There are other tools and methods such as ddrescue, but none are guaranteed to be completely successful.


If the tools do not recovery data then it is gone. Not much else you can do.

  • Thanks @John. That is about what I expected. This has actually been sitting on another drive for the better part of two years. I didn't lose anything I couldn't replace. I was just getting ready to format over the backup and thought I'd try one last time to see if I was able to recover. I'll consider it a loss.
    – matchew
    Nov 13, 2021 at 19:03
  • I amended my answer as it looks like a loss.
    – John
    Nov 13, 2021 at 19:06
  • A couple notes on tools; spinrite is great for cases where the storage platters have lost some of their signal strength, but it can't do anything for mechanical issues, and it fixes the signal in place, so it won't work for a dying disk, and it may in fact spin your disk to death. Recuva (and easus and photorec, and all other tools like them) also exercise the disk so if it is mechanically failing, spend its remaining life getting an image off it with ddrescue, and then use the recovery tool on the image instead of the disk itself (or if its healthy enough, use spinrite before ddrescue). Nov 14, 2021 at 20:07

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