April 2013.  I have had the card for about 4 months and seemed to work fine.  I use it to store additional files on my ultrabook as the solid state drive is small (only 128GB).  About a month ago, the card could not be recognized.  It only lasted about 2 hours, so I thought maybe just a momentary blip.  However, this weekened, it cannot be recognized at all and it has been 3 days.  Sandisk support is not available until the week, so I will update on tech support soon.  However, I did find that the SanDisk indicated there was a defect with some of these cards.  I assume they will replace it, but I have lost lots of hours and a lot of pictures... so I am really bummed and frustrated.From SanDisk: "SanDisk has been made aware of potential product issues involving a very small percentage of its 32GB and 64GB SanDisk Mobile Ultra microSD cards. Under certain circumstances the cards may lock up and the card becomes inaccessible. The issue has been identified and a manufacturing fix has already been put in place. SanDisk stands behind its products and any customer who experiences this issue with the microSD cards cards is asked to contact the SanDisk support center for a resolution immediately." SanDisk