You might have bought a MicroSD card for your Deck. Over time, however, you might notice the speeds start to slow down. In fact, they might slow down so much that they are practically useless. I’m not talking about opening up your Deck with the card still inside (cough Liam from GOL cough). Bad MicroSD cards are usually caused by one of two things: If you bought the card on Amazon, it might be a fake If you formatted the card on the Deck earlier this year (before the end of May), the Deck did a full format as opposed to a quick format, causing your card to be overwritten too much As reported on the Reddit thread, the OP bought a SanDisk 200GB Ultra MicroSDXC UHS-I on Amazon.