An SD card, or secure digital card, is a small removable flash memory card commonly used in digital cameras, mobile phones, tablets, and other portable devices to expand storage capacity. SD cards are very popular for storing photos, videos, music, documents, and other data.
Unfortunately, SD card users often experience the frustrating problem of data suddenly disappearing or getting wiped from the card unexpectedly. This can lead to loss of precious photos, videos, personal documents, and other important files stored on the card. Several factors can cause an SD card to become corrupted, damaged, or wiped unexpectedly.
Physical Damage
SD cards are small, portable storage devices that can easily become physically damaged through improper handling, leading to data loss or corruption. Bending or snapping the card can break internal components and circuitry, rendering the card unusable. Even small cracks in the card’s casing can allow dust or moisture inside, interfering with the electrical contacts.
Exposing the SD card to liquids is one of the most common ways physical damage occurs. Getting the card wet from rain, spills, or submersion can short circuit the card’s intricate interior parts. Once an SD card has been wet, it is unlikely to work again without professional data recovery services. Additionally, extreme heat from direct sunlight or other sources can warp the SD card’s shape and melt internal parts.
Dropping or hitting the SD card can also cause physical damage resulting in corruption or data loss. The impact can knock delicate components out of place or shatter parts of the card. Pocket lint, dirt, and other debris entering the SD card’s slot can also harm the device. Overall, SD cards are not built to withstand drops, flexing, liquids or debris entering their slots. Taking proper precautions to avoid physical damage is crucial for maintaining the integrity of data stored on these devices.
Corruption
One of the most common causes of SD card corruption is file system corruption. This occurs when the file allocation table (FAT) or file directory on the SD card becomes damaged (1). The FAT keeps track of where files are located on the drive, so if it gets corrupted, the operating system may not be able to access the data properly. Common causes of FAT corruption include improper ejection of the SD card, malware, bad sectors accumulating on the card, and sudden power loss while writing data (2).
Additionally, the SD card’s Master Boot Record (MBR) can become corrupted. The MBR contains important partitioning information that tells the device how the storage space is organized on the card. If the MBR is corrupted or damaged, the device may not recognize the card at all or may not be able to access any of the files (1).
In order to recover data from a corrupted SD card, you may need data recovery software or professional help. It’s also important to note that while the files may still be physically present on a corrupted card, they remain inaccessible to the user unless the file system corruption can be repaired (3).
Overall, file system corruption prevents the operating system from being able to properly access, read, and write data to an SD card. This can lead to data loss if the corruption cannot be fixed. Using the card properly, scanning for malware, and avoiding sudden power interruption can help prevent file system corruption.
Improper Ejection
One of the most common reasons for data loss on SD cards is improperly ejecting the card before removing it from a device. Not properly ejecting an SD card interrupts the read/write processes to the card, which can corrupt data or make files unreadable. This is especially risky with smartphones, tablets, and other mobile devices that aggressively cache write operations.
As the Quora article explains, when you improperly eject an SD card, the device may not have finished writing cached data to it. This can partially overwrite files or leave corrupted data on the card. The file allocation table (FAT) which indexes files on the card can also get corrupted.
To safely eject an SD card, it’s important to use the “Eject” or “Unmount” option in your device’s system menus. This ensures any cached writes get flushed, and the card is deactivated before removing it. If you simply pull out the card without properly ejecting, you risk data loss and corruption.
Formatting
Formatting an SD card will intentionally wipe all data on the card. When you format a card, it erases the file system and structures, removing all files and folders in the process. This returns the card to a blank, base state. Accidental formatting is a common pitfall that leads to data loss. It’s easy to select the “Format” option when attempting to eject or initialize a card, wiping it without intending to. Examples of accidental formatting include:
Plugging an SD card into a computer or device and having it automatically prompt to format the card. Users can accidentally click “Yes” without realizing it will erase data (source).
Highlighting the card in Windows Explorer or Finder on Mac, right-clicking, and selecting “Format” instead of “Eject.” This wipes the SD card when eject was intended.
On an Android phone, going into Settings > Storage and accidentally tapping “Format” instead of “Unmount” (source).
Selecting options like “Low-level format” or “Quick format” on a camera menu without understanding it will delete data.
Formatting permanantly removes files by overwriting the storage sectors where data is physically located. However, recovery is possible in many cases using data recovery software until new data overwrites the old. But quick action is required to maximize the chance of restoring files.
Malware
Malware such as viruses can sometimes infect and corrupt files on an SD card, potentially leading to data loss or the card being wiped. Malware may spread to an SD card if it is inserted into an infected device. For example, an Android phone with a virus could infect files written to the SD card, which would then spread if the card is used in other devices [1]. There are a few ways to check an SD card for malware before use: scan it with antivirus software on a PC, use a malware scanning app on an Android phone, or insert it into a Linux device which is less susceptible to auto-running viruses [2]. If malware is detected, it’s best to format the SD card to wipe it completely. To avoid malware infection in the future, only insert SD cards into trusted devices and don’t use cards from unreliable sources.
Device Issues
Problems with the device using the SD card, like a phone glitch, can cause data loss. For example, if a smartphone encounters a serious error while writing data to the SD card, it may corrupt files or make the card unreadable. According to the SD Association, “Poor performing cards can contribute to data loss due to them being manufactured with low quality flash memory or poor engineering.”1 Additionally, bugs in the phone’s OS or firmware could result in improper writes to the SD card, leading to corruption.
One common device issue is sudden power loss or reset during a write operation, which fails to complete properly. The SD card may then show up as blank or with corrupt data after this improper device shutdown. Per the SD Association, surge protectors should be used to minimize damage from power fluctuations.2 Proper ejection of the SD card before removing it from a device is also essential to avoid corruption.
Counterfeits
Counterfeit SD cards are increasingly common and can lead to unexpected data loss or corruption[1]. These fake SD cards are often sold online or from disreputable retailers. They may be labeled with false capacity claims, like a 64GB card that only has 8GB of actual storage. Writing data past the real capacity will overwrite data already on the card, resulting in irrecoverable data loss.
According to reports, certain brands like SanDisk are frequent targets for counterfeiting[2]. Warning signs include abnormally low prices for large capacities, spelling errors on the packaging, lack of security holograms, and poor performance that doesn’t match the claimed specs. Reputable retailers are less likely to unknowingly sell counterfeits.
If you suspect an SD card may be counterfeit, you can use tools to test the actual capacity. But the safest option is to buy from trustworthy sources. The harm counterfeits pose makes it important to be vigilant when purchasing removable storage.[3]
Sources:
[1] https://www.reddit.com/r/hardware/comments/sd10h1/counterfeit_sd_cards/
[2] https://iboysoft.com/sd-card-recovery/fake-sd-card.html
[3] http://www.datarecoveryspecialists.co.uk/blog/beware-of-fake-sd-cards
Recovery
If your SD card was mistakenly formatted or corrupted, resulting in lost data, there are options to recover the deleted files. The best approach is to use data recovery software designed for retrieving data from storage devices like SD cards.
According to CleverFiles, Disk Drill is an effective SD card recovery program for Windows that can restore deleted files even after formatting or corruption. The recovery process involves first scanning the card to identify recoverable data, then letting you preview found files before restoring them.
For step-by-step guidance, 7 Data Recovery recommends a 4-step process using Disk Drill or a similar reputable recovery tool. This involves connecting the SD card, scanning it for lost data, previewing recoverable files, and then restoring them to a safe location.
With the right software and techniques, it’s often possible to recover deleted files from a wiped SD card. However, Disk Drill and other reliable recovery tools are recommended over free online services that may deliver poor results or expose data to risks.
Prevention
There are several steps you can take to help prevent losing data from an SD card. The most important is to regularly back up your data. Copy important photos, videos, and other files from your SD card to other storage devices like an external hard drive or cloud storage. This ensures you have copies of your data if the SD card gets corrupted or damaged.
Also, be sure to properly eject the SD card before removing it from cameras or devices. On cameras, use the “safely remove” option in the menu before taking out the card. For computers and other devices, eject the SD card through the software interface before disconnecting it. Improper ejection can lead to corruption.
In addition, handle SD cards carefully to avoid physical damage, and store them in protective cases when not in use. Avoid exposing the cards to liquids, extreme heat or cold, and electromagnetic fields. Only use trusted brands from reputable retailers to reduce the risk of counterfeits.
Regularly formatting your SD card can also help it function properly and avoid issues. And running antivirus scans on your computer helps detect malware that may infect the SD card when connected.
Following backup, ejection, handling, and maintenance best practices will go a long way in securing your data and preventing loss.