I was playing a ROM and decided to start fresh, so I went through the tutorial until I got to the part where you save for the first time. When I selected a save file and confirmed that I wanted to save, the screen went black and said : 'Error accessing data. Please turn the power OFF and reinsert the Game Card.' After scouring the internet and finding nothing that works, I figured that here would be as good a place as any to ask for help. I think the problem has something to do with the file location, though I'm not sure. The ROM I'm playing, although I don't think it really affects anything, is Rune Factory 3. Anyway, thanks to anybody who helps! -TaintedMythos
DeSmuME is highly unstable. Actually, pretty much all of the NDS emulators are unstable. Have been for a long time. They don't even work half the time. I'm rather surprised you managed to get it working to begin with. Overall, the issue is very likely just due to bugs in the emulator that haven't/can't be fixed. These are just my thoughts from experience, at least. An emulator can only go so far, afterall.
The odd part is the fact that it's been working for a few years now with no problems, and now it just suddenly is broken. Thanks anyway.
