Need some help with SD card. Nintendo 3DS

So I had a 3DS XL until a little over a year ago. I sold it on Amazon cause we needed rent money. When I sold it, I took out the SD card and hels on to it along with all my games. They all sat in a 3DS box in a storage box in just a storage room for all that time. (Not like a basement or attic, just a room.)

Whale yesterday was my birthday and my wife got me a new 2DS, which was great. I remembered I had that SD card and it had a few games on it. (Pokemon Y and Phoenix Wright, plus one other I know.) So I popped it in to the new system and there's nothing on it.

After lots of frustrated fiddling, I discovered that the storage space on the card is taken up, the 2DS shows that it only has about 5000 blocks of space, and the new one I got with the system has about 50,000. I believe. But nothing is showing in the data management. No software, no saved data, nothing. So I put it in my laptop (it has an SD card reader), and the files are there. It shows 3 folders, 2 pretty small and 1 of them is 3 gigs.

So... does anyone have any idea what the problem is? Is there a way to get my data back? I suppose it's possible the card got close to a magnet at some point in the year, but the data still shows up on a laptop? All my games are still working and no data had been lost. I tried signing into my Nintendo account or whatever, but it shows that my account is still logged into my old 3DS and won't let me sign in again. Could that have something to do with it?

Tl;dnr: I have kept an SD card with a few 3DS games on it for over a year, and now my new 2DS says the card is empty, but also has very little storage space left.

Any help would be greatly appreciated, thanks.

Data is tied ot the parent system, it cannot be used by another system unless you transfer data system to system. The process involves you having the parent system on hand. At best you can do now is calling nintendo up & possibly having them transfering licenses to your 2DS, you will be able to recover games but not saves obviously.

License transfer? How does that work? If I'm planning on getting a bigger SD card for this new system, should I do that before contacting them for that?

If it were using your old 3ds, a simple tool within the options handled that process. Since you lack that, Nintendo will give you the info, but fairly sure knowing the details of your NNID & whatnot would be necessary. Yeah, I doubt upgrading the SD card at this moment would be an issue.

Oh, awesome. That sounds great. Thanks a bunch. I appreciate your help.

It is tied to the NNID if there is one and the NNID is tied to the system it is linked too