I have a 2GB SD card that was reportedly unreadable on several digital cameras and computers, and I need to get data from it. When I put it in my Mac using a card reader and check Disk Utility or use diskutil list, it shows up as a 32.1MB disk with no partition map after a long delay. No volumes show up, of course. When I put it in my Debian computer, it isn't mounted, and I also have no idea what its equivalent of diskutil list is.

Because I need to get data from it, I can't repartition it. How do I repair the disk? It's /dev/disk9 on my Mac, and I also have the Debian machine at my disposal.


There's a Linux utility called testdisk that you might try.

Additional info: If you want to try this on Debian the disk devices can be listed with ls /dev/sd* (or sometimes /hd*).

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    You might want to clarify what testdisk does, how to install or use it or at least give us some idea of why it might fix or help with the problem at hand. – Mokubai Jul 13 '14 at 21:41
  • It comes with a man page. – ZuberFowler Jul 13 '14 at 21:49
  • I tried testdisk /dev/disk9 like the manual said on my Mac, and it said "Unable to open file or device /dev/disk9". Is my card definitely hardware-damaged then? – sudo Jul 13 '14 at 22:02
  • That sounds like the SD card isn't just corrupted, but can't be read at all. If it can't be read at all by the OS then to get the data, you're talking about sending it to a place that has specialized equipment. If you get the point you want to try to experiment and write to it, you might start with just the MBR and try testdisk again. – ZuberFowler Jul 13 '14 at 22:08

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