Formatting SD (Windows)

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This is an add-on section for formatting an SD card to work with the 3DS.

If the 3DS already recognizes the SD card, this guide is not required.

本教學僅適用於 Windows 使用者。 If you are not on Windows, check out the Formatting SD (Linux) or Formatting SD (Mac) pages.



  1. 將 SD 卡插入至電腦中
  2. If the SD card has any files and folders on it, copy everything to a folder on your computer
  3. Run guiformat.exe
  4. Select your SD card’s drive letter for “Drive”

    Make sure you choose the correct drive letter, otherwise you might accidentally erase the wrong drive!

  5. Select a size for “Allocation unit size”
    • If the SD card is 64GB or below, choose 32768
    • If the SD card is above 64GB, choose 65536
  6. Enter anything for “Volume label”
  7. Ensure that “Quick Format” is selected
  8. Click “Start”
  9. Click “OK”
  10. Wait for the format to finish
  11. Click “Close”
  12. If the SD card had any files and folders on it before the format, copy everything back from your computer

Common Errors

  • Failed to open device: GetLastError()=32
    • Close everything that may be using the SD card, such as any File Explorer windows.