How do I check my SanDisk SD card?

An SD card, or Secure Digital card, is a small removable flash memory card that is commonly used in portable devices such as digital cameras, mobile phones, and tablets to expand storage capacity ( SD cards come in different sizes and capacities, with standard sizes including miniSD, microSD, and full-sized SD cards. They allow you to store photos, videos, music, documents, apps, and other files on portable devices that have limited built-in storage. SD cards are inexpensive, portable, reusable, and make it easy to transfer files between devices.

Why check an SD card?

Checking an SD card regularly is important to detect potential issues early, recover lost data, and optimize performance. SD cards can develop bad sectors over time that lead to data corruption or make files inaccessible. Running disk checks periodically can identify these bad sectors before they cause bigger problems.

Checking an SD card’s health also allows you to attempt data recovery if files have already been corrupted or deleted. Using data recovery software quickly after data loss gives the best chance of restoring your photos, videos, documents, and other important files. The longer you wait, the lower the chances of successful recovery.

Finally, verifying your SD card’s read and write speeds can confirm it is still operating at its optimal performance level. SD cards will gradually wear out through normal use which degrades speed. If your camera or device feels sluggish saving files, running a speed test on the SD card can determine if it needs to be replaced with a new high-speed model. Regular health checks maximize the life of your memory cards.


Check the physical condition

Before doing anything else, visually inspect your SanDisk SD card for any signs of physical damage. Look closely at the card for dirt, dust, scratches, dents, bent pins, or corrosion on the metal contacts. Any of these physical issues can potentially cause problems with reading, writing, or connecting to the card.

Light scratches on the plastic casing are usually okay, but deep scratches can damage components inside the card. Inspect the metal contacts to make sure they are clean and not corroded. Bent pins can prevent the card from making proper contact in card readers or devices. Even a small bit of dirt or dust on the contacts can interfere with connectivity.

If the card has any significant physical damage like large scratches, cracks, broken pieces, or bent pins, it is unlikely to be recoverable. But if the damage is minor, you may still be able to revive the card and recover data by cleaning it and using data recovery software. Handle the card gently and be careful not to damage it further.

Checking over the physical condition of your SD card is an important first step before trying any other troubleshooting methods. Ensuring the card is clean and undamaged will give you the best chance of fixing issues and retrieving your data.

Put the Card in a Computer or Device

The first troubleshooting step is to insert your SanDisk SD card into a computer, phone, camera, or other device that can read SD cards. See if the device properly detects and mounts the card. Often issues arise because the card is not making full contact in the slot or reader due to dirt, damage, or other debris.

Go to your computer’s file manager or your phone’s storage settings to check if the SD card shows up. It should display the correct capacity, like 32GB or 64GB. If the card does not appear at all or shows up with 0 bytes, it likely means the device cannot properly communicate with the card.

Try gently cleaning the SD card’s contacts with a soft cloth and inserting it into the slot again. If it still does not read, try a different device like a camera or phone. The issue may be with that specific computer or reader. Refer to the sources below on troubleshooting detection issues.


Run a software scan

One of the best ways to check your SanDisk SD card is to run a software scan using built-in tools or 3rd party software. This allows you to scan for errors, test read/write speeds, and check the overall health of the card.

Windows includes the built-in Error Checking tool that can scan for issues. To use it, right-click on the SD card drive in File Explorer, select Properties > Tools > Check. The scan will look for file system errors and bad sectors (Source).

There are also many free third party utilities available. FakeFlashTest and H2testw are two popular options that will perform read/write tests and deep scans to identify potential faults or fakes. Blackmagic Disk Speed Test is great for testing the read/write speeds. Overall, running a software scan is one of the best ways to thoroughly validate your SD card’s health.

Check for errors

One of the main reasons to check an SD card is to scan for any errors or issues. There are a few common errors to look out for:

Bad sectors

Bad sectors are areas on the SD card that can no longer reliably store data due to physical damage or wear. They can cause data loss and corruption. To check for bad sectors, you can use free tools like H2testw or SD Card Formatter to do a full scan of the card.

File errors

Damaged files, missing files, or corrupted files can indicate a problem with the SD card. You may get error messages when trying to open files. Running a scan with recovery software can identify file errors.

Performance issues

If the SD card is very slow when reading or writing data, it could be a sign of errors building up. You can test read/write speeds with tools like H2testw or SDFormatter to see if your card is underperforming.

Test read/write speeds

An important part of checking an SD card is testing its read and write speeds. The speed class rating on an SD card indicates the minimum guaranteed speeds, but the actual speeds may be faster. There are several free software tools available to test the actual read and write speeds of a card. Two common ones are:

  • SD Card Formatter for Windows – includes a simple speed test
  • H2testw for Windows – comprehensive tool for testing speeds and checking for errors

To test speeds, insert the SD card into a card reader connected to a computer. Then launch the software, select the SD card drive, and run the read/write speed test. Compare the results to the speed class rating to determine if the card is performing to specifications. Consistently slow speeds may indicate a faulty or fake SD card.

Check filesystem integrity

It’s important to check the filesystem of your SD card for any errors. A corrupted filesystem can prevent your device from reading files on the card properly. To scan for filesystem errors on your SD card:

1. Insert your SD card into your computer or device.

2. Open the Command Prompt or Terminal app and run the command chkdsk g: /f (replace g with the drive letter of your SD card). This will scan the filesystem for errors and attempt to fix any found.

3. You can also try software like SD Card Formatter which can scan for bad sectors and fix filesystem errors.

Fixing any filesystem errors can help make your SD card readable again and recover data. However, if your card has developed bad sectors, it’s best to replace it, as physical damage can spread. Be sure to back up your SD card data regularly.

Recover lost data

If you have accidentally deleted important files or formatted your SD card, you may be able to recover the lost data using data recovery software. Some options to try include:

Disk Drill – This software can recover deleted files from SD cards. Follow the steps to download, install, and scan the card to find deleted files.

MiniTool Power Data Recovery – The Removable Disk Drive module can help recover deleted data from SD cards. Install and scan the card for recoverable files.

Data recovery software scans the card and attempts to recover deleted files. The sooner you run the scan after deletion, the higher the chance of recovering the lost data. However, recovery is not guaranteed. Backing up important files regularly can help avoid relying on data recovery.

Back up important data

Before formatting your SD card, it’s crucial to make a backup of any irreplaceable photos, videos, documents, or other data stored on the card. As SD cards can fail unexpectedly, it’s risky to have your only copy of important files stored on one. Consider copying your SD card contents to another storage device, such as an external hard drive, a cloud storage service, or another SD card. This ensures you have a safe backup if anything happens to your original card.

Be sure to copy the entire contents of the SD card – don’t just copy individual files. This will preserve the full directory structure. Some backup software like EaseUS Todo Backup allows full SD card backup and restoration.

Once backing up is complete, you can format the SD card without worrying about losing valuable data. Just be sure to keep the backup in a safe place in case you ever need it.