3DS:SD Card

An SD card is a device that stores data. On the Nintendo 3DS, most data (including digital games and their save data) is stored on the SD card rather than on internal memory.

The 3DS / 3DS XL / 2DS use an SD card, while the New 3DS / New 3DS XL / New 2DS XL use a microSD card. You can use a microSD-to-SD or miniSD-to-SD adapter on devices that use an SD card.

This page serves as a landing page for SD card-related actions that you may want to perform.

Copy everything to a new SD card
Follow 3DS:Moving SD Cards.

Format my SD card so that my 3DS can read it
Follow Formatting an SD card.

Check for SD card corruption
Follow Checking SD card integrity.

Reinstall homebrew after losing everything on the SD card
Follow Restoring / Updating CFW.