Rumor has it here's lots of fake memory cards out there.
Did you buy from a reputable vendor ?
VAPCMD
64 GB card - almost full
cant detect in any PC /Mac ...
cannot format .. only shows 31 MB of space when trying to format or seen in property
gets extremely hot

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic