When I first hitsounded my beatmap the whistle sound did work but upon reloading the beatmap there's just no whistle sample all of a sudden (all whistles that I placed and place have no sound). How do I fix this?
You no longer need to hitsound your osu!mania maps when going for rank (and I generally do not prefer to hitsound), but regardless: Check your effects volume first. If it is high enough and you still can't hear anything, reload osu!. If your map uses custom hitsound samples, check them too.