I have a USB disk from which the USB interface, inside the case, failed.

I removed the disk from the case and connected it to another case that is working.

Now, when I connect the disk to my Mac I see the message: this disk is unreadable.

Typing on terminal

diskutil list

gives me

/dev/disk12 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:     FDisk_partition_scheme                        *801.6 GB   disk12
   1:                       0xEE                         375.1 GB   disk12s1

disk utility gives

enter image description here

is there a way to bring this disk to life in anyway or at least read its files before throwing it away?

2 Answers 2


Try to use ddrescue, which should do a block-to-block copy of your hard drive. Then mount the copy with hdiutil and you might be able to find your files.


ddrescue /dev/rdisk12 /path/to/save/the/copy ddrescue.log

Note: you can interrupt the process whenever you want. The progress will be saved to the map file, ddrescue.log.

And then

hdiutil attach -nomount -noverify /path/to/save/the/copy

And you should see a new disk in 'diskutil list'

You can then try to mount the partitions or do data recovery on that image. One tool you can try for data recovery is testdisk.

  • I did not forget you. I have tried your solution but it takes at least 30 hours to finish on my computer and when I was at the middle of the operation power failed and I had to restart... so I will only see if this works, in 30 hours... 😃
    – Duck
    Commented May 20, 2020 at 18:14
  • @Duck Any updates? And this should resume if it is interrupted because it saves its progress to a log file ddrescue.log.
    – Joy Jin
    Commented Mar 21, 2021 at 11:58

In Disk Utility there is an option to restore which may restore your drive but may erase it in the process. If there is nothing you want on the drive, and you're sure there is nothing you want, then you can try erasing and reformatting the drive. You could also try the partition option in Disk Utility to set up partitions and set the format of each. If you do just reformat the drive, you will lose all the info on the disk.

  • 1
    RE: "In Disk Utility there is an option to restore which may restore your drive." -- Under the conditions expressed in the OP, please explain how this is of any help. Do you know what Restore in Disk Utility does? Commented May 19, 2020 at 16:13
  • No i don't know what it does. But the OP has an unreadable disk so it is worth a shot since he has few options. Restore may do nothing but so what? It takes about 2 secs to click on the restore button. It it erases the disk so will most options that i'm aware of. He wants to bring the disk to life he says. So I told of a way to try and fix it...
    – Natsfan
    Commented May 19, 2020 at 16:32
  • There is a completely different approach in the other answer. I offered a simple way to 'bring the disk to life".
    – Natsfan
    Commented May 19, 2020 at 16:35

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