The blog of Windows Wally, a Windows Support Technician helping common people solve frustrating computer problems.

How To Check If An SD Card or SD Card Reader Is Defective?

Reader Question:
“Hi Wally, I bought a Lexar card reader and 16 gb sd card (10 pcs). And a few days later these events recurred. The cards are not visible in the nest of the camera. It does not see the card reader’s nest. I can not diagnose. Help please” – I. Eser., Turkey

Before addressing any computer issue, I always recommend scanning and repairing any underlying problems affecting your PC health and performance:

  • Step 1 : Download PC Repair & Optimizer Tool (WinThruster for Win 10, 8, 7, Vista, XP and 2000 – Microsoft Gold Certified).
  • Step 2 : Click “Start Scan” to find Windows registry issues that could be causing PC problems.
  • Step 3 : Click “Repair All” to fix all issues.

Setting up weekly (or daily) automatic scans will help prevent system problems and keep your PC running fast and trouble-free.

Wally’s Answer: Using SD cards can be difficult if they don’t work. Especially, when you can’t figure out if the problem is in the SD card, its reader, or something entirely different.

How can you check to see where the problem is? Let’s find out!

Does the SD Card not appear in “My Computer” or “File Explorer” at all? then you need to look at these instructions first.


The user is not able to use the SD card but does not know if the SD card or the adapter is even working.


There are many counterfeit and fake copies of branded flash drives out there. Most SD card readers on the market are also cheap and low quality.



Here are some ways to fix the SD cards issue:

How To Check If A New SD Card Has The Advertised Capacity?

You can check if the SD card you bought has its advertised capacity (typically 90% of the advertised amount) by using Chip Genius. It is free.

How To Check If The SD Card is damaged or Not?

You can run a test on the SD card to verify if it is damaged or not. A damaged SD card will need to be replaced. You can use h2testw to run a diagnostics test on the card to make sure if it is in working condition.

Using a damaged SD card can cause data loss anytime. So, it is best to avoid using it.

Is The SD Card Reader Working?

There is a possibility that the SD card reader is not working. To confirm this, you will need to test it with a working SD card.

If you’re using a laptop computer to read the SD cards and you’re running into problems, then you should try using a USB to SD card reader instead. If you already own one, then you should try to replace it.

I Hope You Liked This Blog Article! If You Need Additional Support on This Issue Then Please Don’t Hesitate To Contact Me On Facebook.

Is Your PC Healthy?

I always recommend to my readers to regularly use a trusted registry cleaner and optimizer such as WinThruster or CCleaner. Many problems that you encounter can be attributed to a corrupt and bloated registry.

Happy Computing! :)

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About the Author

Windows Wally is a helpful guy. It’s just in his nature. It’s why he started a blog in the first place. He heard over and over how hard it was to find simple, plain-English solutions to Windows troubleshooting problems on the Internet. Enter: Windows Wally. Ask away, and he will answer.