j.holgate Says :
Here's my specs:
Mac 4x2.5 GHz PowerPC G5 1 GB RAM OS 10.5.8
Samsung Galaxy S II SGH-I777 Android OS 4.0.4 AT&T (USA)
SanDisk 64 GB microSDHC (Class 10 UHC-1 whatever)
Put the microSD card in my phone and I got error "Blank Card." Tried to format through phone - nada. It would say "Checking Card" then go back to "Blank Card." Tried formatting through computer (via a card reader.) First time I tried Mac OS Extended (Journaled.) No luck. Then I tried formatting the card first on the computer as MS-DOS (FAT) THEN putting it in my phone to format via my phone. Bingo! Hooked up my phone to my Mac via data cable, transferred some files over and tested: audio via doubleTwist. Check. Some digital comics via Comicrack. Check. Took a picture (via Vignette camera app,) save to SD storage. Check.
Double-checked to make sure everything works the way it's supposed to and it does. So the moral of the story is if your phone doesn't immediately recognize the card, you may have to format it (to FAT) first on your computer (I'm assuming Windoze would have something similar,) then reformat it again in the phone so that it formats the way it's supposed to. Hope that helps...