Also, though, be aware that exFAT can issue problems. (The data fragmentation error, mostly.) I went to fat32, and everything's better.
The microsd I used to use, I never had data fragmentation errors. The one I use now, I've had it 1 time. I deleted the rom and transferred it again. No issues since. I don't see how people can constantly have issues with this unless they're buying cheap knockoffs.