Do you have a known working SD card that you have used in the past (before upgrading to this 16GB one)? If you do, you can try Win32 Disk Imager and make an image from your old SD card, then take that image and write it to your 16GB SD card. After that complete, then you can see if the 3DS will read it. Problem with this method is the partition will be the same size as the original SD card size.Still doesn't work and I don't think this a counterfeit,I bought it in a famous store.