So, it's not like the overall function is compromised, but it's a pain in the butt and frankly, if it worked once, I don't understand why it won't mount again. I changed back to the old card to see if that was the issue, but even with the old card, the GoPro won't mount directly anymore–I have to use the SD slot. Once I changed the memory card, the GoPro won't mount directly. The issue is that the GoPro used to mount just fine using a USB cable, and I didn't have to bother with taking the memory card out and putting it into an adapter every time I wanted to download media onto my computer.
If there is no other solution, at least I have this option. Thanks for your help! Yes, I can insert the micro SD card into the SDXC slot using an adapter, and it reads just fine (i.e., I can download media off the card).
