I received my 64GB micro SD and installed it into my Samsung Galaxy S3. No issues ... the phone read the card as a 64GB device with just a small loss due to overhead. The issue came when I tried to copy and paste music to the SD using my PC with Windows 7 Pro. It just did not happen. At this moment I still do not know why W7Pro will not read the exFAT formatted card. All my research says W7 has the ability to "see" the device. Anyway I did find a solution. XP has a patch that will allow the use of exFAT device and after I installed this patch to one of my XP systems the issue was solved as far as data transfer between my S3 and the PC. I plug in the cable that came with the phone to my XP system and data transfer worked as it should.