The Same Promblem as occured on my R4, i dowloaded a game and it worked fine, turned off my DS and Switched it back on the next day and it says cannot find ds menu dat, so i put in puter to go to delete the game and the Sd is completlety empty! this is very annoying as i had 30odd games on their that i now think i have lost, have you found a soulution or have you still got the problem?