Fix in 1 min- {a fatal error occurred when running fusee}

If you’re a Nintendo Switch user who’s encountered the dreaded message “A Fatal Error Occurred When Running Fusee,” you’re not alone. This error can be frustrating but fear not – in this comprehensive guide, we’ll dive deep into what causes this issue and provide step-by-step solutions to get your console back on track.

what is “A Fatal Error Occurred When Running Fusee” Message

Before we delve into solutions, let’s demystify this error message. The “A Fatal Error Occurred When Running Fusee” message is a signal that something has gone awry with the Fusee bootloader. This software is instrumental in booting the Nintendo Switch into custom firmware, making it a critical component for those who love to customize their gaming experience.

Common Reasons for the Error

To effectively tackle this issue, it’s crucial to understand what might be causing it. Several common reasons could trigger the “A Fatal Error Occurred When Running Fusee” message. These include:

Outdated or Incompatible Fusee Version

One of the primary culprits is using an outdated or incompatible version of Fusee. Your Fusee version must align perfectly with your Nintendo Switch’s firmware version to work seamlessly.

Corrupted Fusee Bootloader

Another possibility is that you may have inadvertently corrupted the Fusee bootloader during installation. This can happen if the bootloader wasn’t flashed correctly or if the SD card containing it is somehow damaged.

Hardware-Related Issues

While less common, issues with your Nintendo Switch’s hardware can also trigger this error. While we hope it doesn’t come to this, it’s essential to consider all possibilities.

In the following sections, we’ll guide you through troubleshooting steps to address these issues and get your Nintendo Switch back in working order.

How to Ensure You Have the Correct Fusee Version

To prevent the “A Fatal Error Occurs When Running Fusee” message, you must ensure that you’re using the right version of Fusee. Here’s how:

  • Check Your Nintendo Switch’s Firmware Version:
    • Navigate to the system settings on your Nintendo Switch and find your current firmware version. Make a note of it.
  • Download the Latest Fusee Version:
    • Visit the official Fusee GitHub repository and download the latest version compatible with your firmware. Always keep it up-to-date.
  • Install Fusee Correctly:
    • Follow the installation instructions carefully, choosing the correct firmware version during installation.

Steps to Reflash the Fusee Bootloader

If you suspect that the Fusee bootloader has become corrupted, you can attempt to reflash it. Here’s a step-by-step guide:

Step 1:Gather the Necessary Tools:

    • You’ll need a tool like TegraRCMGUI, a USB-C cable, and a computer.

Step 2:Put Your Nintendo Switch in RCM Mode:

    • Follow the instructions for your specific Nintendo Switch model to enter RCM mode.

Step 3:Connect Your Switch to the Computer:

    • Use the USB-C cable to connect your Nintendo Switch to your computer.

Step 4:Open TegraRCMGUI:

    • Launch the TegraRCMGUI tool on your computer.

Step 5:Inject the Fusee Payload:

    • In TegraRCMGUI, select the Fusee payload and inject it into your Nintendo Switch.

Step 6:Wait for the Process to Complete:

    • The bootloader re-flashing process may take a few moments. Once it’s finished, you should see a success message.

Step 7:Test Your Nintendo Switch:

    • Reboot your Nintendo Switch and check if the error persists.

Checking for SD Card Corruption

If the problem persists, it’s essential to examine the SD card containing the bootloader for any corruption. Follow these steps:

  • Remove the SD Card:
    • Power off your Nintendo Switch and remove the SD card from the console.
  • Use SD Card Formatter:
    • Download and install the SD Card Formatter tool on your computer. Insert the SD card into your computer.
  • Format the SD Card:
    • Open the SD Card Formatter tool and format the SD card, ensuring it’s set to its default settings.
  • Reinstall Fusee:
    • After formatting, reinstall the correct version of Fusee onto the SD card.
  • Reinsert the SD Card:
    • Place the SD card back into your Nintendo Switch and reboot the console.

a fatal error occurred when running fusee

Troubleshooting Beyond Software

If software-related solutions don’t resolve the issue, it’s time to consider hardware-related problems. While hardware issues are less common, they can’t be ruled out entirely. Here’s how to approach this:

  • Inspect for Physical Damage:
    • Carefully examine your Nintendo Switch for any physical damage, such as bent pins in the USB-C port or visible hardware issues.
  • Test on a Different Console:
    • If possible, test the SD card and Fusee setup on a different Nintendo Switch to determine if the issue is specific to your console.
  • Consult Nintendo Support:
    • If you suspect a hardware issue or have exhausted all other troubleshooting options, it’s advisable to contact Nintendo’s customer support for further assistance.

General Troubleshooting Tips

Before diving into advanced troubleshooting techniques, here are some general tips that might help resolve the “A Fatal Error Occurred When Running Fusee” message:

  • Check Your Internet Connection:
    • Ensure that your Nintendo Switch is connected to the internet and that your connection is stable. Sometimes, online updates can resolve software issues.
  • Clear Cache and Cookies:
    • Clearing your Nintendo Switch’s cache and cookies can often fix problems related to the bootloader. Follow your console’s settings to clear these files.
  • Try Using a Different SD Card:
    • If you’re using a microSD card, consider switching to a full-size SD card or vice versa. Sometimes, changing the card type can resolve compatibility issues.

Contacting Nintendo Support

If you’ve diligently followed all the troubleshooting steps and the error persists, it may be time to contact Nintendo Support. Here’s how to go about it:

  • Visit the Nintendo Support Website:
    • Head to Nintendo’s official support website ( and navigate to the support section.
  • Choose Your Location:
    • Select your country or region to access the appropriate support options.
  • Contact Options:
    • Nintendo offers several contact options, including phone support, live chat, and email. Choose the method that suits you best.
  • Explain Your Issue Clearly:
    • When you contact Nintendo Support, provide them with a detailed description of the problem, including when and how the error occurs. Be ready to share information about your Nintendo Switch’s model and firmware version.
  • Follow Their Guidance:
    • Nintendo’s support team will guide you through further diagnostics or may arrange for a repair or replacement if necessary.
Error MessageCause
A fatal error occurred when running FuseeThe wrong version of Fusee is being used, the Fusee bootloader is corrupted, or there is a problem with the Switch’s hardware.
Unable to load payloadThe wrong payload is being used, the payload is corrupt, or the SD card is not formatted correctly.
RCM communication errorThe Switch is not in RCM mode, the RCM cable is not connected properly, or there is a problem with the Switch’s hardware.
TegraRCMGUI errorTegraRCMGUI is not installed correctly, the TegraRCMGUI settings are incorrect, or there is a problem with the Switch’s hardware.
BootNTR errorBootNTR is not installed correctly, the BootNTR settings are incorrect, or there is a problem with the Switch’s hardware.
Hekate errorHekate is not installed correctly, the Hekate settings are incorrect, or there is a problem with the Switch’s hardware.

Advanced Troubleshooting Techniques

For experienced users who are still grappling with the error, here are some advanced troubleshooting techniques:

  • Custom Firmware Considerations:
    • If you’re using custom firmware, ensure it’s up-to-date and compatible with your Nintendo Switch model and firmware version.
  • Debugging Tools:
    • Utilize debugging tools to diagnose the issue further. Tools like Hekate and Atmosphere can help identify specific problems within your setup.
  • Community Forums and Resources:
    • Engage with the Nintendo Switch homebrew and modding communities. Online forums like Reddit’s r/SwitchHacks can provide valuable insights and solutions.
  • Back-Up Data:
    • Before attempting advanced troubleshooting, back up your Nintendo Switch data to avoid any potential data loss during the process.
  • Proceed with Caution:
    • When using advanced techniques, proceed cautiously, and only make changes if you fully understand the consequences. A wrong move can worsen the situation.


In conclusion, encountering the “A Fatal Error Occurs When Running Fusee” message on your Nintendo Switch can be frustrating, but with the right approach, you can resolve it. Start by ensuring your Fusee version matches your firmware, try re-flashing the bootloader, and check for SD card issues. If hardware problems persist, contact Nintendo Support for expert assistance.

Remember that customizing your Nintendo Switch comes with some risks, so always exercise caution and follow official guidelines to avoid such errors in the first place.

Frequently Asked Questions (FAQs)

What is the Fusee bootloader?

The Fusee bootloader is software used to boot the Nintendo Switch into custom firmware, allowing for various modifications and customizations.

Why is it essential to match Fusee with my firmware version?

Compatibility is crucial. Using an incorrect Fusee version can lead to errors and instability in your Nintendo Switch.

I've followed all the steps, but the error persists. What should I do?

Contact Nintendo Support for further assistance if you've exhausted all troubleshooting options. There may be an underlying hardware issue.

Can I avoid these errors by not using custom firmware?

using official firmware and avoiding customizations reduces the risk of encountering these errors.

Is it safe to use advanced troubleshooting techniques?

Advanced techniques should only be attempted by experienced users. Proceed with caution and back up your data to avoid potential complications.