I have had a repeated issue and have returned 2 Nooks for new. No one has given me a solution. While playing music loaded on my microSDcard, I'll randomly get a warning box about the music player app not responding, then the Nook will shut down. First solution was to make sure all music was a correct format. I admit I did find some newer songs in a MPEG.4 format. I went through the tedious process of re-formating all the songs to MP3's. Well, it's happened again. I love my Nook, but I'm ready to return it and go for a Kindle Fire. Has anyone but me had this issue and what did you do?
I have not experienced a problem like this on my NT. Since it's happend on both Nooks, it's possible that one of your MP3 files is corrupt or non-standard in format. I've seen this sort of thing on my PC. And don't forget, the Kindle Fire does not support SD cards, so you'll be stuck with limited storage.