Hello, I've been meaning to create an account on here for a while now and seeing your problem inspired me to finally get off my a** and make one so that I may shed some light on your situation. I ran into this same exact problem when I upgraded my SD card to a 128gb one. The problem you are having is in fact your SD card. BBM can only read 100gb of data and if there is more than 100gb of free space on your SD card then it will just crash. A couple of different things worked for me.
1. Download the EaseUS Partition master
http://www.easeus.com/partition-manager/epm-free.html
1b. Resize the partition that your Sysnand is on to 99gb and then click apply to make sure the changes took affect.
or if that doesn't work (as I have had issues with this working with an Emunand set up) try just filling your card with enough .cia files or video files (or anything really) so that there is less than 100gb of free space on the SD card.
It just absolutely
CANNOT have more than 99.9gb