Hero 3 Black freezes after firmware update

[divingpyrate]

The 64gb cards use exfat format not the normal format.
if you formatted it or modified it in a PC or MAC it might have hosed it.
that format is very skittish

 

[RedStang]

I have 3 of these, all three had the same problem: Amazon.com: SanDisk Ultra 64 GB MicroSDXC Class 10 UHS-1 Memory Card with Adapter (SDSDQU-064G-AFFP-A): Electronics

I believe these have a lifetime warranty. May want to follow up with SanDisk if you're outside of Amazon's return window.