How to fix an exception occurred error during CFW install on Nintendo 3DS 

Jul 2, 2019

If you own a Nintendo 3DS or 2DS console, you are probably aware of CFW. Custom firmware is very useful for a lot of reasons.

Installing a CFW can be a bit tricky. One obstacle which I personally encountered during a CFW install, was the infamous ARM 11 error.

I was curious to see what the newly released Luma3DS 10.0 CFW had to offer, and was trying to get the homebrew launcher running via the Rosalina menu.  Once I exited the Download Play app, and re-opened it to open the homebrew launcher, I got the screen that you see above. This step which is a usual part of the install, should have worked, but it didn't.

This tutorial assumes that you are familiar with the popular and well-written guide on 3DS Hacks.

What didn't work for me

How to fix an exception occurred error on Nintendo 3DS

Let me save you some time and tell you what not to do. Naturally when I thought the app wasn't working, and tried a different one. A commonly recommended fix, is to use the Health and Information app, which is pre-loaded on the Nintendo 3DS. But when I tried it, the console threw the same error.

I also tried the Luma configuration menu’s options, which includes the Game patching, and disable ARM 11 errors, to no avail.

How to fix an exception occurred error on Nintendo 3DS

  1. Begin by powering off the console.
  2. Connect the SD card to your computer, and go through the following folders:
    • 3DS folder - This should contain the ctr-no-timeoffset.3dsx and FBI.3dsx. Do NOT place your boot.3dsx file here.
    • The root folder of the SD card - It should have the boot.3dsx file.
  3. If any of those are missing, download and copy them to their corresponding folders.
  4. Open the Download Play app. Once it displays the 2 options, try launching the Rosalina Menu using the key combo: Left shoulder + Down + Select. Set the Switch the hb. title to the current app", and then press B twice to exit the menu.
  5. Close the Download Play app, and re-open it. The homebrew launcher with the CTR and FBI options should now be displayed on the screen.

In my case, I had to re-download the boot.3dsx file and put it in the root of the SD card. I also managed to confirm this was the fix, by deleting the boot.3dsx file and was able to produce the error screen successfully. The only other files involved during the process are the CTR and FBI. So, you may want to try replacing those too, in case the fix didn’t work for you.

How to fix an exception occurred error on Nintendo 3DS
Article Name
How to fix an exception occurred error on Nintendo 3DS
How to fix an exception occurred error on Nintendo 3DS. This could happen during a CFW install. Don't worry, it's pretty easy to fix.
Ghacks Technology News

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  1. Michael Myers said on March 12, 2023 at 6:03 pm

    Hi there, I’m curious if you know why the “An exception occurred” error screen would happen but only sometimes during a Super Smash match on a homebrew console (luna, Twilight, etc.). It only happens sometimes, and I don’t know what triggers it. I’m concerned it could indicate a bigger problem for the console? Or it may be a Smash update issue?

  2. Anonymous said on September 19, 2022 at 6:13 am

    Mine didnt work, but I didnt even try to mod it or anything, I just did a system update. The error happens on system power on, not an app select.

  3. Jaxon said on November 24, 2021 at 7:47 am

    Make sure not to tamper with GodMode9, if you do, you will end up with a hard-bricked 3DS!

  4. Diane said on September 11, 2021 at 9:32 pm

    I bought my 3ds already customized with the firmware. The seller taught me some basics, but I am not sure I can follow these instructions properly. If anyone is w to break it down in simpler terms/steps, that would be great.

  5. Furqaan said on March 11, 2021 at 4:14 pm

    Hello my 3ds have another problem
    My 3ds keep blue light on and nothing appear when i insert a sd card the blue light turn offf

  6. Wolf said on November 19, 2020 at 1:18 am

    am i supposed to delete those crash files off the sd card?

  7. Anonymous said on November 19, 2020 at 12:52 am

    i dont own a computer a
    m i screwd

    1. David Beals said on November 25, 2020 at 5:04 pm

      Get a card reader you can plug into your phone thats how I moded my 3ds.

  8. Anonymous said on September 25, 2020 at 8:49 pm

    followed step by step and it didnt fix it for me

  9. stumfy64 said on September 5, 2020 at 6:36 am

    Thank you so mych!

  10. PapaGarp said on August 21, 2020 at 3:37 am

    Worked instantly. Quick, concise, excellent article.

  11. Anonymous said on April 11, 2020 at 6:52 pm

    Bro! So much thaks to you, bro.

  12. john john said on March 28, 2020 at 3:53 am

    Fran, you didn’t forget. The guide omits the direction to include boot.3dsx as of 3/27/2020

  13. Ammon said on March 20, 2020 at 6:54 pm


  14. Anonymous said on February 18, 2020 at 11:30 am

    Thanks worked for me.
    regards from Brazil

  15. nivk said on January 25, 2020 at 1:45 am

    thankyou so much finallymanafed to hack my ds

  16. Ricardo said on January 22, 2020 at 5:24 am

    Love you, you save my life

  17. Fran said on December 7, 2019 at 11:00 pm

    This worked for me, thank you so much! I was trying to get an old 2DS I’d hacked previously, but had system transferred to a New 3DS. I used the 3DS hacks guide and I must’ve skipped the part where it said to include boot.3dsx on the root of the SD card. Thanks again!

  18. 1c3Bear said on July 19, 2019 at 1:42 am

    Strange, after installing CFW on my :New: 2DS XL. Sometimes, it would show the crash handler while a on the microSD Management function. While not immediate, it still happens often and I’m not sure if there is a solution to why it does this.

  19. bertum said on July 3, 2019 at 6:10 pm

    At least it’s better than the ARM9LoaderHax days. I’d bricked my old 3DS during the 2.x -> (then) current upgrade and was only able to get it back working again when MagnetHax became a thing.

    The 3DS scene is a lot more streamlined these days.

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