Also worth noting, the MicroSD market is littered with counterfeits. Most of us don't scrimp on our MicroSD cards - often "springing" for a Class-10 cards ranging from 90MB/s up to 120MB/s or higher. The quickest, easiest way to tell if you got a "fake" card is to simply copy a large file to the card (like a movie of 2GB or greater). You should see minimally about 60MB/s:
Counterfeit cards will barely make 1/10th that.
This is, by far, the quickest, easiest way to see if your card is meeting its promised throughput rating. Needless to say, due to dismal throughput, fake cards may net the dreaded "Card Missing" error message.