SDXC Card Reader is Read Only

Aloha,

I'm experiencing a strange problem where any SD cards I insert into my SDXC card reader show up as read only. The strangest part is that if I use a usb external card reader these cards show up as read/write. I've validated the toggle switch on the card is on correctly, and have tried various SD cards of varying sizes (4GB SDHC, 64G SDXC). I called Apple support today and went through a slew of testing, including resettting my SMC, resetting my PRAM, using the external card reader to format the cards in various formats (FAT32, journaled, etc.). We created another admin user on the account, but the new account had the same trouble. The most interesting thing we tried was going into restore mode. From within restore mode you can access Disk Utility. At that point I was able to see the SD card AND it was read/write. I was to format the card at that point. When I restarted my macbook pro I left the SD card slotted and when it booted up, the card was read/write, and I was able to format the card. However, as soon as I removed the card and reslotted it, it became read-only again. I did this last step multiple times and was able to reproduce the issue.

Apple decided that this was some sort of software issue and recommended reinstalling my OS. That seems a bit drastic to me at this point however. Has anybody else this issue, or have any ideas on some setting that may be incorrect?

OS X version 10.8.3

Hardware Overview:

Model Name: MacBook Pro

Model Identifier: MacBookPro8,2

Processor Name: Intel Core i7

Processor Speed: 2 GHz

Number of Processors: 1

Total Number of Cores: 4

L2 Cache (per Core): 256 KB

L3 Cache: 6 MB

Memory: 16 GB

Boot ROM Version: MBP81.0047.B27

SMC Version (system): 1.69f4

Regards,

Frank