villapoo
Bought this for Samsung Galaxy S3 in Fall 2012 and that card works perfectly to this day.  Bought the same card in May 2013 for Galaxy S4 and it continuously mounts and unmounts.  Sometimes it is not even recognized by S4 or PC.  Amazon is awesome and pre-shipped a replacement.  It did the same thing, though.  According to Cnet, Sandisk acknowledged a &#34;manufacturing problem&#34; with these cards back in January 2013.  Said it was fixed, but the bad cards must still be sitting in warehouses.  Returned both and ordered Samsung's 64gb micro sdxc card.  $12 more and slightly slower read/write specs, but works perfectly in S4 and I can't tell the difference in its speeds compared to the Sandisk that works in my S3.