The MicroSD reader I had received with my R4, worked once, then when I put it into my R4 to put into my DS, it wouldn't work after that. It will show up as removable disk on My Computer still, but I can't put a file on it. It will say to check my path and try again. I don't know what that means. I can't format it, and when I click on properties it says 0 bytes. Now I can access the card through my phone and thats how I've been accessing it on my computer, but it's really slow. Any help will be appreciated. Thanks.