I have an 8gb Micro SD card that I use for my Nintendo DS (with M3 adapter). Recently, I accidentally removed the USB adapter from the computer while transferring files to the card.

Now my computer can't read the card anymore (I've tried with two different USB adapters), it just says I have to format the card before I can use it. But here's the thing, the DS can still read the contents of the card and use the files just fine. I'd like to avoid having to reformat if at all possible, since the files are all there and working.