How do You Recover Data from a microSD Card that Cannot be Read?

How do You Recover Data from a microSD Card that Cannot be Read?


We have all been there and had a storage device of some kind experience a failure, leaving our precious data at risk. But what do you do when the device in question is a microSD card? Today’s SuperUser Q&A post comes to the rescue for a reader in need.

Today’s Question & Answer session comes to us courtesy of SuperUser—a subdivision of Stack Exchange, a community-driven grouping of Q&A web sites.

Photo courtesy of Seeweb (Flickr).

The Question

SuperUser reader RockPaperLizard wants to know if it is possible to recover data from a microSD card that cannot be read:

I am trying to help a friend who is very concerned that she has just lost all of the data on her 32 GB SanDisk microSD card. I told her I would post this and see if anyone could help.

Here are the details:

  1. The microSD card is less than two years old (probably about a year old). The store will take it back, but that does not really help. She wants her data.
  2. She used the card in her Samsung Galaxy S4 smartphone for over a month. The phone was never exposed to water or temperature extremes.
  3. Today, her phone suddenly said something along the lines of: “Your SD card is blank or an unsupported format.
  4. Her phone was then unable to read the microSD card at all.

Here is what she has tried:

  1. Rebooting her phone had no effect.
  2. She took the microSD card out and put it inside a full-size SD card adapter, then inserted it into a Windows 7 SP1 computer. The computer did not recognize its presence at all.
  3. She then put the microSD card into a USB 2.0 external card reader and inserted the card reader into a USB port on a Windows 7 SP1 computer. The computer recognized the card reader and installed drivers for it. The card reader shows up as ‘Removable Disk’ in Windows Explorer, but clicking on ‘Removable Disk’ in Windows Explorer results in the error: “Insert disk: Please insert a disk into the Removable Disk.
  4. After trying #3, she tried opening the ‘Removable Disk’ in FreeCommander. Doing so resulted in the error: “The device is not ready.

She does not have access to a Linux computer, but does have access to her Android phone. What can she do to recover the data from her microSD card?

Is there any hope of recovering the data from this microSD card?

The Answer

SuperUser contributor Bob has the answer for us:

You could try pressing the card together (in case it became a little loose?) and maybe cleaning the contacts with a little bit of Isopropyl alcohol on a swab. But I really would not expect any results, and at best you might manage to read some of the data off of it before it dies again. I would not recommend opening it up under any circumstances. That will not help with recovery at all and it will likely cause further damage.

You could also try various alternative readers. If you manage to find one that can at least expose the card as a block device, then you can take an image of the data. While recovering useful data from an image of damaged media is a whole other exercise, it is still better than where you are now.

Sometimes, there just is not anything that can be done. If the data is very important, you could consider professional data recovery services (do they even exist for SD cards?), but they would be very expensive. Otherwise, she might just have to accept the loss and try to recreate what she can.

When a storage device becomes physically unreadable, undetectable even, you cannot go through the normal home data recovery steps (take image, scan for what files you can, etc.). With a mechanical drive, at least common failure modes are partial, so you can at least read something. With the nature of NAND storage, I can think of three possibilities:

  • You have lost the controller. The flash chip itself might still be readable, but reassembling the data from it will be a long and arduous task. This is not doable at home, and requires expensive, professional tools and expertise. If you had the equipment to solder tiny chips (image & source) and read NAND flash, I suppose you could attempt this yourself, but you are more likely to accidentally destroy it.
  • You have lost the flash chip itself. In this case, I do not think there is anything you or anyone else can do. It would be even harder to recover than a lost controller.
  • The card is physically damaged, but the controller and flash memory are intact. This is probably the best you can hope for. Again, with how small and fragile the card is, there is not much you can do at home, but the chance of professional recovery is far higher.

The problem with all of these is that they require very expensive and still uncertain services to even attempt a recovery. Is the data worth that much?

Perhaps the best thing to do is to treat this as a lesson on backups. Always have at least one extra copy of any data you cannot afford to lose. The more important it is, the more copies you want, stored separately from each other.

Special Note: This particular ‘recovery story’ had a happy ending, so make sure to browse on over to the discussion thread linked below to see how things turned out.

Have something to add to the explanation? Sound off in the comments. Want to read more answers from other tech-savvy Stack Exchange users? Check out the full discussion thread here.

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