64GB MicroSDXC on Macbook Air 11

I recently purchased a MicroSDXC reader and paired it with a 64GB. My Macbook Air 11" on Mountain Lion is not recognizing the card.

Paired with a 32GB MicroSDHC card, it is recognized just fine. From reading some posts here, it looks like SDXC should be supported on my machine.

Am I missing something and is there something I can do to make it work?

Note that I tested the 64GB MicroSDXC card and reader on a Windows 7 laptop and it works just fine. Tried formatting the card as FAT32 as well instead of exFAT.