Why do SD cards break?

SD cards are a convenient and popular form of digital storage, commonly used in cameras, phones, and other devices. However, SD cards can unexpectedly stop working or “break”, resulting in data loss and frustration for users. Understanding why SD cards break allows us to prevent failures, recover data when possible, and choose alternative storage options when needed.

The reliability of SD cards is important because they store valuable photos, videos, documents, and other data. An SD card failure at the wrong moment could mean irrevocably losing precious memories and information. For heavy SD card users like photographers, a broken card could ruin a critical photo shoot or event. Even typical users can find a failed SD card highly disruptive.

By examining the main reasons SD cards break down, we can identify best practices for maximizing longevity and minimizing data risks. Though failures are inevitable for this storage medium, knowledge is power when it comes to managing and troubleshooting SD card issues.

How SD Cards Work

SD cards contain a controller chip and flash memory. The controller chip manages the transfer of data between the card and device, while the flash memory actually stores the data.

Flash memory inside the SD card is organized into blocks. Each block contains a set number of bytes for data storage. When a device needs to write data to the card, the controller finds available blocks, erases them, and then writes the new data.

To keep track of where data is located, the controller maintains a file allocation table (FAT). This table maps out what blocks contain the data for each file. When a device needs to access a specific file, the controller looks up its location in the FAT.

SD cards use NAND-type flash memory. This provides high storage density but can only be erased and rewritten in blocks, not bit-by-bit. Wear-leveling techniques help distribute writes across all blocks to maximize longevity.

Cards use serial communication protocols like SPI to transfer data. Multiple pins connect the SD card and device for power, ground, clock, command, and data.

There are different types of SD cards optimized for certain use cases. SDHC offers higher capacity storage while SDXC enables even greater capacity exceeding 32GB. Transfer speed depends on the SD card class rating.

Overall, the controller and flash memory inside SD cards enable high-capacity storage that can quickly transfer files between devices.

Reasons for Failure

SD cards can fail for a variety of reasons. The three main categories of SD card failure are physical damage, corruption, and manufacturing defects.

Physical Damage

SD cards have fragile components that can break if exposed to physical shock, bending, or moisture (Source). Dropping an SD card, getting it wet, or snapping it in half are obvious ways to destroy the card. But even small impacts like sitting on a card in your pocket can damage the interior components over time.


The files stored on an SD card can become corrupted in different ways. Improperly ejecting the card, malware infection, conflicts between devices, or excessive heat exposure can all lead to file corruption (Source). The card may seem to work at first, but you’ll encounter errors when trying to open files as the corruption spreads.

Manufacturing Defects

While rare, some SD cards leave the factory with defects. Components may be assembled incorrectly or low-quality materials used. These issues lead to premature failure compared to properly manufactured cards. There’s often no way to identify a defective card until it stops working.

Physical Damage

One of the most common causes of SD card failure is physical damage. Dropping, bending, or scratching an SD card can damage the delicate components inside. According to Damaged Micro SD Card Data Recovery, “A physically damaged Micro SD card can indeed result in data loss.”

Dropping an SD card, especially onto a hard surface, can break the small solder joints inside the card. Even a small amount of damage to these joints can prevent the SD card from being read by devices. Scratches on the surface can destroy the contacts needed for the SD card to interface with devices. According to PitsDataRecovery, “Physical damage to an SD card, such as bending, exposure to extreme temperatures, or moisture, can significantly reduce its lifespan.”

Exposure to liquids can short circuit an SD card’s electronic components. Even a small amount of water getting inside the SD card’s plastic casing can lead to corrosion over time. The metal contacts are susceptible to rust and other types of degradation from moisture.

Bending an SD card can crack the silicon wafer inside, the key component that stores data. With the wafer damaged, data cannot be read from or written to the card. The thinner the SD card, the more susceptible it is to damage from bending. Even slight warping is enough to permanently damage some cards.


One common cause of SD card failure is corruption of the data on the card. This can happen for several reasons:

Improper ejection – If you don’t properly eject the SD card before removing it from your device, it may not finish writing data to the card. This can cause file system corruption. Always safely eject SD cards before removal to prevent data loss or corruption (Source).

Malware – Viruses and other malware can sometimes attack the file system of an SD card and corrupt data. Always scan new SD cards with antivirus software before use (Source).

Power loss – If power is lost while the SD card is being written to, it can cause corruption. Avoid removing batteries or losing power while the card is in use to prevent this issue (Source).

File system corruption can often be repaired using data recovery tools. But severe corruption may require reformatting the SD card, resulting in data loss. To avoid corruption, always properly eject SD cards and maintain reliable power while the card is in use.

Manufacturing Defects

SD cards can fail due to manufacturing defects that arise during the production process. These issues mainly come down to faulty components or insufficient quality control. According to Fstoppers, a teardown analysis of defective SD cards found problems like:

  • Faulty or low-quality NAND flash memory chips
  • Contaminants introduced during manufacturing
  • Soldering problems on the SD card’s circuit board
  • Components not properly attached during assembly

Manufacturers may cut corners to reduce costs, use flawed materials, or fail to implement adequate quality control checks. This results in SD cards with inherent defects right from the start. Even big brands like Samsung and SanDisk can have issues if their factories don’t maintain sufficiently high standards. While manufacturing faults don’t account for all SD card failures, they are a contributor.

Preventing Failures

There are several steps you can take to help prevent SD card failures and data loss.

Proper Handling

Be gentle with your SD card. Avoid dropping it, getting it wet, bending it, or exposing it to extreme heat or cold. The contacts in particular are vulnerable to damage, so be careful when inserting and removing the card. Keep the card in its protective case when not in use.

It’s also important to properly eject the card before removing it from your device, using the “Safely Remove Hardware” function. Simply pulling out the card without warning could cause corruption.

Buying Quality Cards

Invest in SD cards from reputable brands known for reliability, like SanDisk, Samsung, or Sony. Avoid cheap cards that may be more prone to defects and premature failure. Check reviews before purchasing to ensure consistent positive experiences with durability and performance.

Pay attention to the card’s speed rating as well. Faster cards are built with higher-quality components. A UHS Speed Class 3 card or above is recommended for optimal stability.

Backing Up Data

As with any storage medium, it’s essential to back up your SD card data to another location in case of failure. Copy your photos, videos, and other files periodically to your computer hard drive or cloud storage. That way, if your card becomes corrupted or damaged, you won’t lose anything irreplaceable.

For best practices, refer to this source: https://gadgetmates.com/how-to-check-sd-card-health-on-your-mac

Recovering Data

If your SD card has become damaged or corrupted, there are a few options for attempting to recover the data. Software tools like CHKDSK on Windows or Disk Drill can scan the SD card and recover files that are still intact. CHKDSK attempts to repair file system errors while Disk Drill can recover data even if the file system itself is corrupted.

For physical damage like a broken SD card, professional data recovery services may be required. They use specialized tools to repair SD cards and read data off the memory chips directly. This is the best option for recovering data from a severely damaged SD card, but it can be expensive. The success rate depends on the extent of the physical damage.


While SD cards are convenient for adding storage to devices, there are alternatives worth considering that may be more reliable or have other advantages:

Cloud storage services like Dropbox, Google Drive, Microsoft OneDrive, and Apple iCloud provide abundant storage that is accessible from anywhere with an internet connection. Data stored in the cloud is also regularly backed up and synchronized across devices. However, access does depend on having an internet connection.

External SSDs (solid state drives) connect via USB and provide very fast data transfer speeds, better durability with no moving parts, and capacities up to 2TB currently. Models like the Samsung T5 are compact and don’t require external power. But external SSDs are currently more expensive per gigabyte than SD cards.

Adding internal storage may be an option depending on the device. For example, some laptops allow upgrading the built-in SSD. Internal storage offers faster speeds than external, but often requires opening up the device.

While no storage solution is failure-proof, alternatives like cloud storage, external SSDs, and internal storage upgrades provide useful options beyond SD cards.


In summary, SD cards can fail for a variety of reasons, including physical damage, file corruption, and manufacturing defects. To maximize the lifespan of your SD card, handle it with care, avoid extreme temperatures, reformat it regularly, and purchase reputable brands. Make sure to back up your data, as recovery can be difficult. While SD cards are convenient, for archival storage, consider alternatives like external hard drives or cloud backups.

To avoid losing important photos, videos, and other data, be proactive about prevention and backup. With proper care and maintenance, SD cards can reliably store your files for years. But all storage media has a limited lifespan, so migration to new devices is inevitable. Check your SD cards periodically and retire any that show signs of failure. Though inconvenient when it happens, a bit of planning can prevent a SD card failure from becoming a catastrophe.