It now appears that it's my memory card [official SanDisk 64gb] that is having issues. Have a couple files in LOST.DIR folder and for the life of me, I cannot format the card in Android or Windows. Either says failed or success but regardless, all my files are still on the card and can be mounted, read, and written to without any real trouble.
Really wish to avoid buying another card unless I have to. I've had all 3 Notes and they all have killed an sd card at least once. I almost think it's Sammy's fault.
Can anyone point me in a direction? Most things I've searched for are fixing dead cards, haven't found anything about cards that work but won't format.
Thanks for any help you can offer!