I've gone through 6 San disk 64gb class 10 cards between my Note 2 and Note 3 with my last cropping out 2 weeks ago. San disk will replace your card and tell you to contact the phone manufacturer. I did that contacted Samsung...at 1st I got the run around but I was persistent and got a hold of a good tech support agent. Samsung phones have issues writing info to the 64gb class 10 cards. They are aware of the issue and are working on a fix as of 2-3months ago. He told me the will work fine. He said they don't recommend over 32gb and a class 4 card because of the stability issues of files being corrupted on class 10s particularly 64gb 1s. Funny thing is i called San Disk back and told them what i was told and asked for a 32gb lower class and he told me i could buy it buy they could only replace it with the same one i had. Good luck!
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