3DS:Error screens/Luma3DS exception screen

This page lists possible causes and fixes of Luma3DS exception screens. They are not applicable to every situation, but cover most common known issues.

Reading a Luma3DS exception screen
A Luma3DS exception has four (or five, in a few cases) different parts to it that help in finding its cause, as follows:
 * Processor: What part of the system is causing the exception. The two processors are:
 * Arm9: The 'security processor' of the system. These exceptions usually result from errors in NAND data or hardware faults in either the 3DS or its SD card.
 * Arm11: The 'userland' of the system. These exceptions have numerous causes but are often related to broken software or user data.
 * Exception type: How the system is causing the exception. These categories are often too broad to be helpful, but three of them are more precise:
 * data abort: Oftentimes related to a broken mod or broken HOME Menu data. Occasionally related to custom firmware data being broken.
 * prefetch abort (svcBreak): Oftentimes an issue with data on the NAND, even when Arm11. Can also happen when launching an out-of-region game.
 * undefined instruction: Usually either a broken piece of software (if not on boot) or outdated  (if on boot).
 * Fault status: Why the system is causing the exception. Normally not helpful except for developers.
 * Current process: Where the error is coming from in the system. Often the most helpful part of the exception. Some examples of processes are as follows:
 * fs: The filesystem, i.e. either the SD card or the NAND.
 * menu: Data that is opened either as a part of the HOME Menu or at the same time as it.
 * loader: The service that opens apps, meaning the app you last tried to open has an issue.
 * nwm: Networking services, almost always WiFi.
 * ns: The N intendo User Interface S hell, which handles all apps/processes/services in 3DS mode.
 * R0: Usually just internal data that's not worth reading. There are two notable exceptions, however:
 * Arm11 loader exception: If R0's contents start with a C or D, R0 is an error code. This code usually gives the exact cause of the issue.
 * Arm11 pm exception: If R0's contents are,   is guaranteed to be too outdated to work.

Known Errors
In the following list, the file prefixes on file paths refer to the starting location. refers to the SD card, and numbers in the format of  refer to GodMode9's drive numbers.

Arm9
Arm9 errors are sorted by their exception type.

Error On Boot

Any Type
 * Files on the SD are corrupted.
 * To fix, verify that your SD card is not faulty. If it is verified working, make a backup of all intact files, format the SD card, and try booting again.
 * A system save located on the NAND in  has a problem.
 * System-unique files are missing from the NAND in.

data abort
 * The  folder in   is missing.
 * To fix, create this folder.
 * System titles have been deleted.
 * To fix, perform a Safe Mode update. If this does not work, perform a CTRTransfer.

prefetch abort (svcBreak)
 * The system movable,, is 288 bytes but a flag is enabled that expects a size of 320 bytes.
 * To fix, boot into GodMode9 and select, then go into the   folder. Inside this folder, you will see a file named  . Select it, and under the options menu, select Show in Hexeditor. Green-colored numbers will appear in the middle of the screen - press  and then unlock writing to sysNAND (lvl2). At the beginning of the file, look for the set of numbers  . Once you find these numbers, hold  and press  while the   value is highlighted to change it to  . Press , then , then  to save changes and exit from the hexeditor, then press  to reboot your console.
 * has bad CMACs.
 * To fix, press R+A on the  drive and  . The console will act like it has been formatted after this, and this is intended.

prefetch abort (kernel panic)
 * The console likely has a hardware issue.

undefined instruction
 * The console likely has a hardware issue.

Error During Use

data abort
 * Files on the SD are corrupted.
 * To fix, verify that your card is not faulty. If it is verified working, make a backup of all intact files, format the SD card, and try again.

Arm11
All Arm11 errors are sorted by their current process.

Error On Boot

boss
 * The current firmware version is too old for SpotPass to work. Perform a Safe Mode update.
 * If this does not work, you may require a CTRTransfer.

fs
 * Could be an SD card problem, minor NAND problem, hardware issue, or anything in between.
 * fault isolation will likely be required to find the true cause of this error. Start by doing ctrcheck, formatting your SD card, and/or testing your SD for errors.

hid
 * Potential hardware problems, or an outdated version of Rehid.
 * First look for and delete  and  . If these dont exist, or you've never downloaded Rehid, it's likely hardware issues.
 * 3ds_hw_test or ctrcheck may help with fault isolation.

ic2/spi
 * The console has a serious hardware issue that is likely not easily fixable.
 * Join the Nintendo Homebrew Discord and ask, in English, for help.

mset
 * System Settings is broken in some way - this may indicate that the console has a hardware issue.
 * To fix, perform a CTRTransfer, or a Manual CTRTransfer if that does not work.
 * If neither of these work, the console has a serious issue. Join the Nintendo Homebrew Discord and ask, in English, for help.

menu
 * data abort
 * The installed theme is corrupted or otherwise broken.
 * To fix, go into the folder  and delete the folder matching your region, one of the following:
 * USA: EUR:  JPN:
 * The HOME Menu's extra data is corrupted.
 * To fix, go into the folder  and delete the folder matching your region, one of the following:
 * USA: EUR:  JPN:  KOR:
 * An installed application is corrupted or otherwise broken.
 * To fix, either perform a Safe Mode update, attempt to enter System Settings before the crash occurs and delete the application in Data Management, or reformat the SD card.
 * prefetch abort
 * An installation of menuhax is conflicting with the custom firmware.
 * To fix, follow the directions on this page.
 * prefetch abort (svcBreak)
 * The  folder in   is broken, its exact location being at.
 * To fix, backup  by pressing R+A while highlighting it, then selecting  . Once it is backed up, delete the folder. If this does not fix the issue, copy the folder back where it was.

ns
 * The Luma configuration setting  is set to boot to a title that does not exist.
 * To fix, disable the option or install an application that matches the title ID set in.

nwm
 * The WiFi chipset's hardware is damaged or dead.
 * To fix, replace the WiFi chipset with a new one. To avoid the error until then, disable WiFi on the 3DS and do not turn it back on.
 * If the 3DS is an old model, you can disable WiFi with an external switch. New models must instead disable it through the HOME Menu Settings or Rosalina. Repeatedly pressing the keycombo for Rosalina while powering on might let you access Rosalina before it can crash.

pm
 * The installed version of Luma3DS likely does not support the current firmware version. This is guaranteed to be true if the contents of R0 are.
 * To fix, update CFW.

Error During Use

3dsx_app
 * The  file you opened is corrupted.
 * To fix, download a new copy of the  file. If this error happens when you open the Homebrew Launcher, download a new copy of.
 * If the error still happens, test your SD for errors.

app/CtrApp
 * The app you last opened is trying to use broken software.
 * To fix, disable all game mods, cheat codes, and plugins to ensure they are not the cause.
 * If the error still happens, then the game itself is likely faulty. If it is a system app, perform a CTRTransfer. Otherwise, if it is a cartridge dump, redump it, if it is an eShop game, click the Repair button at the bottom of its eShop page or delete and reinstall it, or if it is a cartridge, clean the cartridge and the 3DS cartridge reader with isopropyl alcohol.

GARDEN Animal Crossing's game data or savedata is having issues.
 * To fix, disable all game mods, cheat codes, and plugins to ensure they are not the cause. If the error still happens, then the game itself may be faulty. If it is a cartridge dump, redump it, if it is an eShop game, click the Repair button at the bottom of its eShop page or delete and reinstall it, or if it is a cartridge, clean the cartridge and the 3DS cartridge reader with isopropyl alcohol.
 * If the error yet still happens, ensure that you have not used a save editor before the error started happening. If you have used a save editor, the edits are broken and you will need to restore a backed-up save, or wipe the save and start over if you have no backup.

fs
 * Could be an SD card problem, minor NAND problem, hardware issue, or anything in between.
 * fault isolation will likely be required to find the true cause of this error. Start by doing ctrcheck, formatting your SD card, and/or testing your SD for errors.

Kujira/Joker/niji_loc
 * The app you last opened has an issue of some kind.
 * To fix, disable all game mods, cheat codes, and plugins to ensure they are not the cause. If the error still happens, ensure the game is the same region as the console - if it is not, force the game to use the correct region.
 * If the error yet still happens, then the game itself is likely faulty. If it is a cartridge dump, redump it. If it is an eShop game, click the Repair button at the bottom of its eShop page or delete and reinstall it. If it is a cartridge, clean the cartridge and the 3DS cartridge reader with isopropyl alcohol.

loader
 * The app you last opened has an issue. If the contents of R0 start with C or D, R0 is an error code.
 * Most of the possible error codes for this are listed on this page.

mset
 * System Settings is broken in some way - this may indicate that the console has a hardware issue.
 * To fix, perform a CTRTransfer, or a Manual CTRTransfer if that does not work.
 * If neither of these work, the console has a serious issue. Join the Nintendo Homebrew Discord and ask, in English, for help.

nwm
 * The WiFi chipset's hardware is damaged or dead.
 * To fix, replace the WiFi chipset with a new one. To avoid the error until then, disable WiFi on the 3DS and do not turn it back on.
 * If the 3DS is an old model, you can disable WiFi with an external switch. New models must instead disable it through the HOME Menu Settings or Rosalina. Repeatedly pressing the keycombo for Rosalina while powering on might let you access Rosalina before it can crash.

qtm/cam
 * The camera's hardware is damaged or dead.
 * To fix, replace the camera with a new one. To avoid the error until then, disconnect the camera or avoid using anything that activates the camera.