- Open the Terminal app.
- Type
diskutil list external physical
, then find the SD card and take note of its disk name. It will look likedisk2
ordisk3
. - Once you are sure of the SD card's disk name, type
diskutil unmountDisk /dev/disk#
, where # is the number in the disk name you found.- If the system cannot unmount the disk, type
diskutil unmountDisk /force /dev/disk#
to forcibly unmount it.
- If the system cannot unmount the disk, type
- Type
diskutil eraseDisk FAT32 NAME MBRFormat /dev/disk#
.- Replace
#
with the disk number, and replaceNAME
with any name that does not begin with3ds
.
- Replace
- Once the format is complete, copy your data back onto the SD card.