I bought it at best buy - a 32gb Sandisk Ultra Class 10 MicroSDHC card. I bought it with the intent of using it with a DSTwo I haven't received yet from Realhotstuff, but I currently have a CycloDS Evo that I use often with an 8gb MicroSDHC card that seems no name brand with no issues. Whenever I try and copy games and files onto it, or delete files, it says "Copying..." and hangs indefinitely. I left it on over night and it stayed copying, and considering it's an 8mb file, I don't think any more is going to be an issues. When I first got the card I didn't have a problem putting two games on it really quick and trying it with the CycloDS(games ran perfect), so I can't understand why it's doing this now. I've formatted it multiple times, as well. Is it my card reader? It works perfect with my other card, just this one gives me the trouble. But since it's class 10 I figure it could be the reason it's giving me issues? The other one is class 4. Or is it a defective card that I should hike back to best buy and return? Or is it my computer? I can take a picture. The box says "Discovering items" indefinitely.