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Why Did My SD Card Fail?

August 25, 2023

SD (Secure Digital) is a popular data storage format developed by the SD Association, a joint partnership between several major flash manufacturers. 

The SD format encompasses a number of related technologies:

  • SDHC
  • microSD
  • miniSD
  • SDIO
  • SDXC
  • SDUC

All SD formats are non-volatile flash memory — and as such, SD cards are generally more resistant to physical damage than hard drives or other magnetic media. However, no data storage format is perfect.

Data loss for SD cards can present a variety of symptoms:

  • Files appear corrupt or unreadable.
  • Files or folders “disappear” from the file structure. 
  • The computer doesn’t recognize the SD card when inserted.
  • The computer recognizes the SD card, but reports an inaccurate capacity (for example, a 128GB SD card shows a size of about 30 megabytes). 

Generally, SD card recovery has an excellent prognosis. However, flash memory must be treated in an appropriately outfitted data recovery laboratory — in most circumstances, your local computer store will not have the tools to safely recover your files. 

Common Causes of SD Card Failure

Below, we’ll discuss common causes of SD card failure. To learn about’s SD recovery services, call 1-800-237-4200 or schedule a risk-free evaluation online.

1. Firmware Corruption 

From a hardware perspective, SD cards are simple devices: They contain a printed circuit board (PCB), memory chips, and a controller that allows the card to interface with a reader. 

If the firmware becomes corrupt, the SD card may be completely unreadable. More often, it will present an inaccurate capacity. Your computer may ask whether you want to format the card — don’t reformat the card (unless you don’t care about the data).

Reformatting the card may resolve firmware corruption temporarily. However, exercise caution when storing data on an SD card that has lost its formatting or shown other signs of firmware corruption; the device will almost certainly encounter the same issue again. 

2. Data Corruption

Flash media stores data with electricity. In another article, we explained the basics of flash storage, but here’s the short version: A series of transistors hold electric charges to represent your data. 

Over time, the transistors become less reliable, which can be exacerbated by user behavior: 

  • If you use your SD card regularly, the repeated writing/erasing causes memory wear, which raises the chances of corruption.
  • If you let your SD card sit in storage for an extended period of time, charge leakage may cause corruption.
  • If you unplug your SD card from your machine without going through a “safe disconnect” process, corruption may occur.
  • If you suddenly shutdown an application or your computer’s operating system while it writes to the SD card, corruption occurs.

Corrupt files may be unreadable, despite appearing to have an accurate size, format, and other details. Corrupted images may be partially viewable, but a portion of the image may show random visual artifacts. 

3. Virus or Malware Infection

Malware infection is rare for many SD formats. Usually, you’re using the SD card to store a specific type of data (such as images or videos), not for general data storage.

However, data is data, and malicious software doesn’t really discriminate. Malware may target any storage device attached to a computer or smartphone. 

To resolve the infection, data recovery engineers will need to identify the source of the malware or ransomware. Learn more about our ransomware recovery services.

4. Accidental Deletion

Because of the methods that flash devices use to store data, deleted files may be unrecoverable once the operation executes. If you accidentally delete files or format your memory card, we strongly recommend ejecting the SD card immediately. Learn why we do not recommend using data recovery software for addressing accidental file deletion

If the files are important, contact a professional data recovery provider as soon as possible. provides a no data, no charge guarantee, and all of our flash memory recovery services include risk-free price quotes.

Get started by scheduling a media evaluation online or call 1-800-237-4200 to speak with an expert.