How can I retrieve data from a SD Card when photorec doesn't work?

Question

A friend of mine took pictures of a Halloween party with his camera, and when he put the SD card in his computer, some of the pictures went missing. Knowing that I have successfully rescued his HD with testdisk, he asked me if I could do something about it. I told him no to use the SD card anymore until I can do something with it, in order to prevent remaining data to be erased.

I first opened the SD Card folder in Nautilus, and I got this error:

Quick translation: Impossible to show content of this folder, I/O error on weird filename

This weird file was nowhere to be seen in Nautilus. Moreover, when right clicking on the "112_FUJI" folder, selecting "properties", it tells me that the folder holds for more than 21GB of data, and the SD Card has a capacity of 8GB...

I ran photorec on the SD card, got many things back (wanted as well as unwanted stuff: mp3, doc, zip, aif files), but none of the picture he took that night. (Just to clarify, we're 100% sure he took the picture, that they were recorded to the SD, that we didn't deleted them, AND that I'm working on the good SD card)

So, I told him that my recovering skills ends at the same point that testdisk and foremost does, and told him I could do nothing more for him. But then, I opened the SD card folder with a terminal emulator, and I found something else:

(please note that this is only the end of the ll command in the folder, there are a few more weird files/folder at the beginning, but the end was more relevant for a screenshot)

So there seems to be a bunch of files and folder that are here, but that I can't access for some reasons (Bad sectors? Anything else? I don't know, my skills aren't that extended). Anyway, they might be the picture we're looking for (pun intended), but as you can see, this is a huge mess. Non-ASCII characters, unknown rights on the files, ... (and we might have an explanation of why it says it holds more than 8GB)

So here are my questions:

1. How can I retrieve data of those files/folder (assuming they are the pictures I'm looking for)
2. How did this mess happened? How to prevent it (but this is just me being curious, the priority is to get back the data)

Thanks to anyone who helps.

Answer 1

You may well be close to the end of the line for "regular" data recovery. What I would do is use (GNU) DDRescue to make a bitcopy of the SD card - or as much of it as you can get, and then try use Testdisk to Repair the FAT Tables (ie by looking at the backup copy of the File Allocation Table)

You might also - on a bit copy of the drive, attempt to run checkdisk /f to try and force it to fix the drive - this might help - it might also make the problem a lot worse.

Its anyones guess how the problem happened - the card going faulty is, I suspect the most likely cause, it could also have been a problem with the firmware/software in the Camera, and/or maybe it came loose during the middle of a write.

Answer 2

SD cards are prone to hardware problems. Once such a problem has occurred, the card needs to be replaced.

For recovering the data, the best recovery programs are :

1. MiniTool Power Data Recovery (Free Edition)
   I count it as the best of its kind. Available on Windows and Mac. The free version has a limit of 1GB of recovered data.
2. Recuva
3. TestDisk
4. PC Inspector File Recovery
5. Puran File Recovery