Failed to mount SD card! (13)
Try reformat your SD card to FAT32.
Error #01: Nintendo 3DS folder not found!
Ensure that your 3DS is recognizing your SD card. Since it's highly likely that your SD card FAT32 at this point, ensure that:
- The lock slider on your SD card is in the unlocked (up) position.
- You are inserting the SD card into the 3DS's SD card slot, and not a flashcart. (Nintendo Support: How to insert an SD card or microSD card)
- the 3DS's SD card slot is not dusty or clogged.
After that, try power on the console with the SD card inserted. If the Nintendo 3DS folder still does not exist, then the SD card slot may simply be broken.
Hold L+R+↓+B while powering on your 3DS. When prompted to reset the HOME menu management info, select Reset.
Error #05: No Mii Maker extdata found!
Ensure that you are launching Mii Maker (not StreetPass Mii Plaza!) with your SD card inserted.
Error #06: Insufficient SD card space!
At minimum, 16 megabytes is required to make a copy of the files required to trigger MSET9. It is recommended to free up at least 2x that amount, so that you won't be barred from uninjecting MSET9.
The NAND backup created by Finalizing setup requires up to ~1.3GB of space, so you should ideally free up that much.
Error #07: You have multiple (#) ID0's!
This usually happens because the SD card has been use in multiple 3DS consoles (or the console has been formatted since you last used the SD card).
Consult: 3DS:Troubleshooing/Multiple ID0
Error #08: One or more files are missing or malformed!
Please re-download the MSET9 Release .zip and extract the files to the root of your SD card. If you are prompted to replace any files or merge any folders, do so.
Information #10: No title database!
This usually happens when there is no eShop software on your SD card.
The visual guide to reset the title database is here.
Error #12: You have multiple (#) ID1's!
Consult: 3DS:Troubleshooting/multiple ID1