That's interesting, not sure what could cause it. It's possible the BRSTM file may be corrupted, or somthing. Have you tried listening to the BRSTMs not working in BrawlBox before trying them in-game?
Yeah. I've tested them in Brawlbox & they work fine but then they will completely stop being read in-game. I hear it for so long then it stops & since I use Riivo I notice that my Wii Light flashes when it's reading something but when it trys to read these strange songs (it works if redownloaded sometimes but does the same sometimes too so it's not the song itself) it flashes normaly then stops & it's like it stops reading. The Song stops too.
