microSD card not working properly or being reocgnized

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http://forums.androidcentral.com – I bought a 64GB Samsung microSDHC card (class 10) online yesterday for my GS3, and it seems that it isnt receiving the files correctly. I think it may be because I formatted the card before I used it, but these are the 2 problems: 1. when i copy and paste movies or videos onto the card, it will not play on my GS3 or on my laptop for that matter. 2. when i copy and paste over 2000 mp3 files onto the card, only 567 files will be pasted (those 567 mp3s play fine though) ive deleted the files and try to paste them again and no luck, and a lot of hours wasted. I've also formatted the card (HowTos)