As a portable memory device, SD card came into our life and brought us much convenience. To be honest, SD card has a wide application range; it can be used in digital camera, mobile phone, MP3/4 player, game machine, etc. Thus, I feel it’s necessary to talk about SD card file recovery in this post.

Retrieve Files from SD Card That Is Inaccessible

Please read the following phenomena that indicate SD card damage to see whether you are familiar with them or not. The corresponding steps to retrieve files from SD card will be given later to help you get rid of data loss disaster.

Phenomenon 1: Location Is Not Available

After you connected SD card to computer and clicked on the drive that stands for your SD card, you get the prompt message: “* is not accessible”. (You can confirm that this problem is caused by file system failure by just reading the information on the prompt window)

location is not available

Fix "Location Is Not Available" Error

Phenomenon 2: You Need to Format the Disk before You Can Use It

You’re asked to format the SD card you’ve connected to computer through a data line when you try to open it. It’s obvious that: only after you allowed formatting the card by clicking on “Format disk”, you’re able to use the SD card again to manage data and save new files. On the contrary, if you tap “Cancel” instead, you are still not able to enter the SD card.

need to format the disk

You Need to Format the Disk before You Can Use It

Phenomenon 3: Drive Is Not Accessible

You may also see this prompt when trying to access the SD card on computer: “*:\ is not accessible”. At this time, you can only click “OK” to close the prompt window, but that problem still exists and you’re still not able to see any files in the SD card.

disk is not accessible

No matter which situation you’re in face of, the only right choice at that very moment when you see those error messages is seeking methods for retrieving files from SD card without wasting a minute.

How to Recover Data from Inaccessible SD Card

In fact, the direct reason why those phenomena appear is that the SD card has been damaged whether due to accidental formatting or other operations.

This post tells how you can recover a formatted SD card.

Considering this, I plan to offer a good solution to helping you get data back from damaged SD card. Then, you can reformat the SD card so as to get rid of the inaccessible problem.

I suggest you employ MiniTool Power Data Recovery right after disaster appeared.

SD card recovery software

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Here’s how to retrieve files from an inaccessible 4GB Micro SD card in only 4 steps:

Firstly, you’re supposed to use a card reader or other tools to connect your SD card to computer. After that, you can open the computer to check whether it is recognized by system or not. Then, launch the MiniTool Power Data Recovery after you can see the SD in computer Disk Management.

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Secondly, you should select “Removable Disk Drive” from the left pane to locate your SD card quickly. Then, you should select the target 4GB SD card and press “Scan” to start searching for all lost files in it.

select Removable Disk Drive & press Scan

Thirdly, you’re supposed to look through all possible partitions listed in the software and try to select all the files you’d like to recover.

look through partitions to select files

Finally, press “Save” button in the lower right corner to specify a storage location for files needing to be recovered and tap “OK” to confirm.

Note: If the software has helped you find what you need, you should get an advanced edition to accomplish data restoration (you may click on the “Upgrade Now” button shown in the picture below to get a license).

Reading here, you must have mastered the way to recover files from formatted drive well. What are you waiting for? You’re encouraged to try to do the recovery work on your own under the help of this wonderful data recovery software.

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Why SD Card Becomes Inaccessible

Compared to internal computer hard drive, SD card is relatively weak. Since SD card is featured with great portability, it can be taken out and moved from one place to another easily.

This also increases its possibility to fall victim to a lot of factors:

  • Virus infection.
  • System corruption
  • Dust or oil stain
  • Unstable voltage
  • Squeezed slot

Let’s get to know these reasons better.

Virus Infection

Virus has been detected almost everywhere in today’s digital era and virus is regarded as one of the biggest threat to data saved in multimedia storage devices. You can easily get your SD card infected during data transmission with other devices. Therefore, you can’t be too careful when using the SD card, which has important data stored in.

Besides, you can get an antivirus program to check whether the card has been attacked by virus. But what you should remember is: please don’t kill the virus or format the SD card until you have retrieved all files deleted by virus successfully.

File System Corruption

Frankly speaking, file system refers to the methods and data structures used by operating system to keep track of files on a disk or a single partition. It decides the way how files are organized on the target drive.

Once the file system is broken, you’ll lose your access to files saved on that drive. That is to say, you’ll be prevented from entering your SD card if its file system is corrupted.

file system corrupted

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Dust or Oil Stain

As some of you may haven’t protected the SD card chip well every time when you take it out from original device, dust or oil stain will occur and accumulate on the surface, making SD card fail to be recognized by any device or computer.

In this case, you can stare at the surface of SD card chip carefully to see whether there is much dust and whether the metal region is dim or covered by spots. If it is the fact, you need to wipe the surface of SD card chip gently by using eraser or the cotton which has been moistened with alcohol or water.

Unstable Voltage

A high-quality SD card has a high requirement in power supply. So if the battery used in your SD card devices is not original, but an inferior product, you will meet data access failure.

At this time, you are strongly suggested to change the battery for an original or superior one. If it still failed, you probably ought to recover data from inaccessible SD card with the help of professional recovery companies or programs. And then, buy a new card.

Squeezed Slot

For some SD card supported equipment, especially the slim machine, the slot design is very clever. And if non-original or non-formal battery is used, the slot may be squeezed since the thickness exceeds a certain standard.

Here is the fact - no matter what the reason is for causing SD card inaccessible and data loss problem (it doesn’t matter if the SD card is improperly formatted or damaged physically), the first thing people will think about is absolutely how to retrieve files from SD card. I’m sure that you will care much more about data rather than the SD card which stores them in most cases. Certainly, this is reasonable and the right thing to do.

Pay Attention to the Following 5 Things

One: Browse Photos on Computer

Try to look through the photos you have taken with digital devices on a computer after taking out the SD card and connecting it to computer properly. Of course, you also need to do so if you’re planning to modify the photos.

The direct modification in SD card increases the possibility of getting your SD card crashed. What’s more, the modification of a lot of pictures may lead to SD Card “paralysis”.

connect SD card to computer

Two: SD Card Gets Stuck or Crashed

If the device which contains a SD card is getting stuck or crashed, this indicates that there’s a serious trouble with your SD card. You may see a prompt asking you to format the SD card in this situation.

But remember; please don’t allow doing so until you have recovered data from inaccessible SD card successfully. After that, you can choose to format the SD card for further use. Anyway, I don’t suggest you save important files into that SD card again since the same problem is likely to occur every now and then.

Three: Get High-quality SD Card

When you’re selecting a SD card, please try to choose the genuine products. You must avoid getting pirated and counterfeit products with an amazingly low price or beautiful appearance. And the situation is the same when you’re searching for a good card reader.

Four: Plug in or Eject SD Card Properly

Please don’t feel troublesome to plug in or unplug the mobile SD card properly to the computer in order to manage data in it well. Instead, you should do exactly as required to connect an SD card properly; besides, you must safely remove it from computer when you don’t need to use it.

Do You Really Need To Safely Remove USB Device?

safely remove SD card

Five: Do the Recovery at First

If the following problems occur after you have connected an SD card to computer, please don’t take actions to try to fix the problem immediately.

  • Drive letter loss
  • Data inaccessible
  • Messy codes
  • Capacity turning into 0 bytes
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The first thing you should do is figuring out ways to retrieve files from SD card safely. Then, you can do whatever you want to do.

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Data Read and Write Of SD Card

There exist two modes in the reading and writing of SD card data: Single Block Mode and Multiple Block Mode.

  1. Single Block Mode: the host will read and write a data block according to the pre-defined length. A 16-bit CRC check code will be generated by the transmission module and the receiving terminal will check by using this check code. Unaligned access is not allowed, so each block must be located within a single physical sector.
  2. Multiple Block Mode: the host can read multiple data blocks (of same length) at the same time; it may read data from or write data into contiguous memory addresses according to the address in command. The operation will be ended by a stop transmission command.

Please keep reading the following content to know how to read a data block from and write a data block into SD card.

Read a Data Block from SD Card

This whole process is very easy.

  1. The host gives a “READ_SINGLE_BLOCK” command and set the starting byte address as a parameter.
  2. Then, SD card will check this address and send a R1 command as response to that action.
  3. If this kind of SD medium read/write operation has been finished, a starting data token, a fixed number of data and the two bytes of CRC - 16 checksum will be sent. If SD card hardware failure or read/write failure occurred, any one of them will not be sent; instead, an error token will be sent to stop data transmission.

Write a Data Block into SD Card

This process is similar to the data block reading process.

  1. Initialize the write operation by sending a “WRITE_BLOCK” command.
  2. Then, the SD card will respond in R1 command responding format.
  3. If the command gets a response, it indicates the operation can be carried out. So the host will send a starting data token, a fixed number of data and the two bytes of CRC - 16 checksum and then end this procedure.
  4. Now, SD card will send back a data response command to indicate whether the data waiting to be written into SD card are acceptable or not to determine the subsequent operations.


As I have mentioned before, a SD card is easy to fall victim to a lot of reasons and all data in it may be lost, making you suffering a lot.

But after reading the above content, I guess you have mastered the way to deal with such terrible situation (knowing well about how to recover data from inaccessible SD card with ease). So good luck with everyone, hope you all can retrieve files from SD card without trouble.

How to Retrieve Files from SD Card FAQ

How do I recover pictures from my SD card?
  1. Connect the SD card to your computer via a card adapter.
  2. Install and run MiniTool Power Data Recovery.
  3. Select Removable Disk Drive and click Settings.
  4. Choose the picture types you need and click OK.
  5. Scan the SD card and choose needed pictures to recover.
How can I recover my mobile data from SD card?
You can use MiniTool Power Data Recovery and follow the steps above to recover SD card mobile data. You can also connect the mobile directly to computer and run MiniTool ShadowMaker to scan the SD card & recover mobile data.
How can I recover data from corrupted SD card?

There are actually many ways to help users recover data from a corrupted SD card.

  • Run CHKDSK command to check for errors.
  • Use reliable data recovery software.
  • Reinstall/update the driver.
  • Assign a new drive letter to SD card.
  • And so on.
How can I repair my SD card without formatting?
  1. Scan and repair: open File Explorer to locate the SD card -> right click on it to choose Properties -> shift to Tools tab -> click on the Check button.
  2. Run CHKDSK: open Windows search -> type cmd -> right click on Command Prompt to choose Run as administrator -> type chkdsk *: /f /r /x (* is the drive letter) -> hit Enter.
  3. Assign a new drive letter: open Disk Management -> find the SD card and right click on it -> choose Change Drive Letter and Paths -> restart your computer.
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