I purchased this card (the 64GB version) to use in a Samsung Galaxy S2 phone. It worked perfectly for almost three months, at which point it just stopped mounting. The phone detects a card, but is incapable of formatting it. It's even worse on my computer, which does not even detect the card anymore (and yes, I'm using an SDXC-compatible USB reader).I contacted SanDisk for an RMA and they will probably replace it, although the replacement process is needlessly slow and painful.I had bought this card based on the glowing reviews, but I'm going to stay away from SanDisk products from now on.