I usually use the following command to start Jupyterlab: jupyter lab --no-browser After I start a browser, it immediately shows the following error and warning messages: [IPKernelApp] ERROR | No such comm target registered: jupyter.widget.control [IPKernelApp] WARNING | No such comm: 8d87f402-5f…

Hello kdlin1, assuming you work in a Python environment, can you please run $ python -m pip freeze and give us the resulting packages, their versions and whether this is a virtual environment (if so tell us what environment). If you not working with Python, just issue $ jupyter --version on the cmd…

I can reproduce this on an NVIDIA Jetson (aarch64) - it’ll take me a couple of hours to trim things down to a minimal example. It doesn’t seem to be affecting the operation of my applications. Also, this environment is frozen at Python 3.6, so “get a newer Python” is not a solution.

Hi, sorry for the late response. I use conda to manage the packages. Will your command still work?

I run Python 3.8.13. The same problem is still there.

It turns out this is an ipywidgets issue. It was fixed in 2017 but apparently some package constraint solvers still give a version that’s broken. See https://github.com/jupyter-widgets/ipywidgets/issues/1721 . There’s a workaround here: https://github.com/jupyter-widgets/ipywidgets/issues/1721#issuec…

According to the following Github issues, this error and warning are harmless. The project maintainers are working on a change that will result in these messages not being generated in the first place. More information can be read here: ipywidgets don't work on vir…

IPKernelApp Error and Warning

JupyterLab

kdlin1 May 3, 2022, 5:58am 7

It is unclear to me what one needs to do to fix the issue you mentioned. Could you please elaborate a bit?

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IPKernelApp Error and Warning

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