What Causes SD Card Corruption?
There are several common causes of SD card corruption:
Physical damage to the card such as scratches, bends, or water damage can lead to corruption by damaging the internal components (source). If the card is bumped or jostled while reading or writing data, the head can jump tracks and mix up the data. Additionally, removing the card while it is still reading or writing can corrupt the file structure and file system.
Power loss or removal of the card during operation can cause corruption by interrupting read/write processes before they are complete. This can leave files partially written or the file system structures in an inconsistent state (source).
Errors in the file system structures or damage to file system metadata can render the data on the card inaccessible. Malware infections can also damage the file system by modifying or deleting critical OS data (source).
Signs of a Corrupted Card
There are a few key signs that indicate your SD card may be corrupted:
- You receive error messages when trying to access data on the card. For example, you may see “SD card error” or “cannot read from the device.” This indicates the device cannot properly read data from the SD card (source).
- You cannot access or view data that was previously saved on the SD card. The files may be missing entirely or appear corrupted. This suggests the file system or data itself has become damaged (source).
- The device does not recognize the SD card at all. It may fail to mount or not show up as an available storage device. This points to corruption in the card’s formatting or metadata (source).
In general, if you cannot reliably read data from or write data to an SD card, it is likely corrupted.
Can Reformatting Fix Corruption?
Reformatting an SD card essentially recreates the file system on the card. This process erases all data and partitions on the card and writes a new blank file system table. Reformatting can potentially fix software-related errors that may have caused corruption. By wiping the card completely clean and starting fresh with a new file system, any software bugs or glitches can be eliminated.
However, reformatting will not fix physical damage to the SD card. If there are bad sectors, electrical issues, or degraded flash memory chips on the card, reformatting cannot repair these hardware problems. The corruption will likely recur even after reformatting in these cases. Reformatting only addresses software and filesystem issues, not defects with the physical components of the card.[1]
So in summary, reformatting may resolve SD card corruption caused by software errors, but cannot fix corruption caused by hardware damage or deterioration. It’s worth trying a reformat as an initial troubleshooting step, but if the corruption persists, the card likely has physical defects that require replacement.
Steps to Reformat
Before reformatting an SD card, it’s important to try and backup any data that can still be accessed. Copy files off the corrupted card onto another storage device if possible.
The best tool to use for reformatting an SD card is the official SD Card Formatter tool available from the SD Association. This formatter will completely erase and reformat the card to FAT32 or exFAT as needed.[1]
To reformat, download and install the SD Card Formatter tool on your computer. Insert the corrupted SD card into the computer’s card reader. Open the SD Card Formatter and select the drive letter for your SD card. Choose Quick Format and click Format to start the process. This will fully reformat the card and erase all data.
After reformatting, test the SD card by taking some sample photos or videos with your camera. If the card works properly and saves files without issue, the reformat succeeded. If the card is still corrupted or malfunctions, reformatting did not fix the problem.
When Reformatting Fails
If reformatting the SD card does not resolve the issue, there are a few other things you can try before considering the card corrupt and unusable.
First, try reformatting the card using a different computer or operating system. For example, if you first tried reformatting on a Windows PC, try your Mac computer or an Android smartphone instead. The card may format successfully on a different device. According to EaseUS, sometimes the issue is with the computer or device rather than the SD card itself.
You can also test the integrity of the SD card using a program like h2testw. This will scan the entire card and check for errors. If errors are found, it indicates physical damage to the card that likely requires professional data recovery to fix. As suggested by StellarInfo, h2testw can identify if an SD card is actually usable or corrupted beyond typical troubleshooting.
If you’ve tried other computers, OS options, and integrity checks to no avail, the card is likely facing irreparable corruption. At this point, you may need to use a professional data recovery service if the data on the card is valuable and irreplaceable. They use specialized tools to repair the file system and extract data. However, data recovery can be expensive and not guaranteed. Formatting is not able to fix this level of physical corruption.
Data Recovery Options
If reformatting the SD card fails to fix the corruption, there are a few options for trying to recover the data:
Try recovery software: Specialized SD card recovery software like EaseUS Data Recovery Wizard or Recuva may be able to scan the card and restore lost files and folders. Many paid and free options are available.
Send to a data recovery service: For valuable or irreplaceable data, a professional data recovery service may be able to recover data even from a severely corrupted card. This can be expensive but offers the best chance if software can’t recover files.
Data may be unrecoverable if hardware is damaged: If the SD card has physical damage or corruption at the hardware level, it may not be possible to recover any data. Formatting or attempting recovery on a damaged card risks overwriting files. In these cases it’s best to contact a specialist before taking any action.
Preventing Corruption
There are several key steps you can take to help prevent SD card corruption in the first place:
Always safely eject the card before removing it from your device. Suddenly disconnecting the card while it’s writing data is a common cause of corruption. Refer to your device’s manual for proper ejection procedures.
Avoid removing the card during active read/write operations. Wait until transfers are fully complete before taking out the card. The best practice is to only insert and remove the card when the device is powered off.
Invest in high-quality, name-brand SD cards from reliable manufacturers. Lower-grade cards are more prone to corruption issues over time. Select cards designed for your device’s specification needs.
Regularly back up important data and photos stored on the card. Don’t use the SD card as your sole copy of irreplaceable content. Copy files to another secure storage location.
Remember to safely format your card in the device it will be used in before each major usage. Formatting helps prevent file system issues.
Alternative Storage Options
There are several alternatives to SD cards that may work better depending on your needs:
Cloud Storage: Services like Google Drive, Dropbox, iCloud, etc. allow you to store files remotely instead of on a local SD card. This gives you access from multiple devices and protects against physical loss/damage. However, you need an internet connection to access the files.
External SSD: Portable external solid state drives connect via USB and provide very fast transfer speeds, more storage, and better reliability than SD cards. But they are pricier and bulkier.
USB Flash Drive: Also called thumb drives, these plug into a USB port and allow transfer of files. Larger capacities like 128GB are available. The small size is a plus but speeds are slower than SSDs.
Internal Drive: For devices like laptops and PCs, an internal drive like an HDD or SDD provides more space. But it’s not portable and you’d need to install it into the device.
When to Replace a Card
There are a few telltale signs that indicate it’s time to retire an SD card and replace it with a new one:
Frequent corruption issues – If you find yourself frequently encountering corrupted files or errors when trying to access data on the card, it likely means the card is reaching the end of its lifespan. SD cards can gradually deteriorate over time.
Visible damage – Carefully inspect the card for any cracks, dents, bends or corrosion on the contacts. Physical damage can prevent proper function. If you see any visible damage, it’s best to stop using the card.
Errors persist after reformatting – Try reformatting the card to see if that resolves intermittent issues. If problems persist even after a format, it’s a sign the card is no longer reliable for storing important data. Reformatting cannot fix a fundamentally failing card.
As a rule of thumb, SD cards used frequently should be replaced every 2-3 years. And any SD card that is showing signs of age through frequent errors should be retired. Continuing to use an unstable, damaged or aged card risks permanent data loss. Replace old cards proactively to ensure your important photos, videos and files are preserved safely.
Sources:
https://www.slrlounge.com/replace-memory-card-qa/
Summary
Reformatting an SD card can potentially fix software-related corruption issues by erasing the card and creating a new filesystem. However, it usually won’t fix physical damage to the card’s circuitry or memory chips. Before replacing the card, try running data recovery software to retrieve photos and files. Also, keep backups to limit relying on just the SD card.
To prevent corruption going forward, use safe practices like properly ejecting the card, avoiding overfilling it, and handling it carefully. Periodically reformatting cards can also help avoid issues building up over long-term use. But remember, reformatting removes all data, so always backup first.
