How to Fix the Failed to Start Kernel Error in VSCode Jupyter Notebooks

Struggling with the `Failed to Start Kernel` error in VSCode Jupyter Notebooks? Our comprehensive guide will help you resolve this issue swiftly and effectively. --- This video is based on the question https://stackoverflow.com/q/73146944/ asked by the user 'Anthony Ankrah' ( https://stackoverflow.com/u/12161321/ ) and on the answer https://stackoverflow.com/a/73185468/ provided by the user 'Anthony Ankrah' ( https://stackoverflow.com/u/12161321/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions. Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: vscode jupyter failed to start kernel Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l... The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license. If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com. --- How to Fix the Failed to Start Kernel Error in VSCode Jupyter Notebooks If you're a data scientist, a student, or just a Python enthusiast using VSCode for Jupyter notebooks, you might encounter the frustrating error message: Failed to start the Kernel. OSError: [WinError 123] The filename, directory name, or volume label syntax is incorrect:. This error can halt your workflow and leave you scratching your head. Fortunately, the solution is often straightforward. Understanding the Problem This kernel failure is commonly due to a mismatch in versions between the ipykernel package that's installed with Anaconda and what the Jupyter extension for VSCode expects. The good news is that you can easily rectify this issue with a few simple commands. Symptoms You May Experience Code cells in Jupyter notebooks do not execute. Error messages indicating kernel failures appear repeatedly. Log outputs show OSError related to incorrect filename or directory syntax. Step-by-Step Solution Here’s a clear path to fixing this kernel error. Follow the steps below to get your Jupyter notebooks up and running smoothly: Step 1: Launch Anaconda Prompt Begin by opening the Anaconda Prompt on your machine. This is where you'll enter the necessary commands to update the part of your system that controls the kernel. Step 2: Update ipykernel In the Anaconda Prompt, type the following command: [[See Video to Reveal this Text or Code Snippet]] This command updates the ipykernel package to the latest version compatible with your Jupyter environment. Step 3: Reload the VSCode Window After running the update command, switch back to Visual Studio Code. Here’s how to refresh the interface: Press Ctrl + Shift + P to open the Command Palette. Type and select Developer: Reload Window. This ensures that VSCode recognizes the changes you've made regarding the ipykernel. Step 4: Test Your Notebook Open up your existing Jupyter notebook (with the .ipynb extension) and try executing a cell. The kernel should start without any issues, allowing you to run your Python code seamlessly. Conclusion Encountering the Failed to Start Kernel error in VSCode can be frustrating, but with the steps outlined above, you should be able to resolve the issue quickly. Keeping your packages, especially ipykernel, up-to-date is crucial for maintaining a smooth coding experience in Jupyter. If the problem persists after following these steps, consider checking your Jupyter log for additional insights, or ask for further assistance from the community. Happy coding!