I checked SanDisk’s official guidelines, and SanDisk microSD cards don’t actually have unique serial numbers, which explains why the automated product registration bot couldn’t accept it. I believe a reliable way to verify authenticity is to test the memory card’s capacity and speed.
On a Windows computer, you can download and run H2testw.
Select “Write + Verify” to fill the full 128GB capacity. If an error occurs or it displays “Capacity unstable,” your memory card is very likely a counterfeit.
As far as I know, SanDisk Extreme Pro has read speeds up to 200MB/s and write speeds around 90MB/s–140MB/s. You can use benchmarking tools like CrystalDiskMark (Windows), iBoysoft DiskGeeker for Windows, or Blackmagic Disk Speed Test (Mac). Counterfeit memory cards typically have slow write speeds, with a maximum speed between 10MB/s and 18MB/s. If your write speed cannot consistently exceed 60-90MB/s, it is very likely a counterfeit product. Read also: How to Tell a Fake SD Card and How to Fix & Recover
