ModuleNotFoundError+No+module+named+jupyter+server

Not specified by the original author.

TL;DR: notebook 7 needs the separate jupyterserver package and it is missing. Run `pip install jupyterserver` and notebook launches.

The error

ModuleNotFoundError: No module named 'jupyter_server'

Fix it

1. Install jupyter_server:

   pip install jupyter_server

   Expected: install completes.

2. Verify:

   python -c "import jupyter_server; print(jupyter_server.__version__)"

   Expected: prints the version.

3. Launch notebook again. Expected: the server starts instead of the import error.

When this applies

Use this when jupyter notebook (version 7+) fails with the jupyter_server error, common after --no-deps installs.

When it does not apply

If you are on classic notebook 6.x, jupyterserver is not needed; a different problem is at play. If jupyterserver is installed but the error persists, check your environment.

Compatibility

notebook 7.x with jupyter_server 2.x.

Root cause

notebook 7 was rebuilt on top of jupyter_server instead of carrying its own server code. The dependency is declared, but installs that skip dependencies or partial upgrades can leave it out.

Edge cases

Installing plain pip install notebook pulls jupyter_server automatically; the error mostly hits hand-assembled envs. In conda, install notebook from conda-forge to get the matched server.

GitHub issue jupyter/notebook#5440 reports ModuleNotFoundError: No module named 'jupyterserver' when launching notebook 7 in an environment where the server package was not installed. The verified fix: notebook 7 split the server into the separate jupyterserver package, so installing it (pip install jupyter_server, which notebook 7 normally pulls in) resolved the launch. Full thread: https://github.com/jupyter/notebook/issues/5440

Not specified by the original author.

TL;DR

JupyterLab is running fine, but the python environment behind your kernel never got ipykernel installed, so no kernel process can start. Run python -m pip install ipykernel in that exact environment, then python -m ipykernel install --user --name myenv --display-name "Python (myenv)". The kernel then appears in the launcher and connects on the first try.

ModuleNotFoundError: No module named 'ipykernel'

Use this when

• JupyterLab opens but starting any python kernel fails with ModuleNotFoundError for ipykernel.
• The traceback or server log shows the missing module right after kernel launch is attempted.
• A fresh conda env or venv shows up in kernelspec list but cannot start.

Not for this skill when

• The kernel starts and then dies mid-cell. That is a crash, not a missing package.
• JupyterLab itself will not launch. That is a server-side install problem.

Steps

1. Find which python the kernel spec uses: jupyter kernelspec list, then read the argv in the spec's kernel.json. Verify: you know the exact python path.
2. Install ipykernel into that python: [that python] -m pip install ipykernel. Verify: [that python] -c "import ipykernel" succeeds.
3. Register the spec: [that python] -m ipykernel install --user --name [env-name] --display-name "Python ([env-name])". Verify: jupyter kernelspec list shows the entry.
4. Restart JupyterLab and pick the new kernel in the launcher. Verify: the kernel status dot goes solid and 1+1 executes.
5. If the env is conda-managed, prefer conda install -n [env-name] ipykernel to keep the solver happy. Verify: conda list -n [env-name] ipykernel shows it.

Variant phrasings

no module named ipykernel jupyter

The generic search. Same missing-package fix.

ipykernel not installed kernel error

Log-style phrasing. Install into the kernel's python, not the server's.

jupyter lab kernel not found ipykernel

Launcher-side phrasing. The registration step is what makes it appear.

Compatibility: JupyterLab 3/4, notebook 6/7, ipykernel 6.x. The install-and-register flow is the same on pip and conda.

Why it happens

JupyterLab and the kernel are separate processes, often from separate environments. The Lab server only needs jupyter_server; the kernel needs ipykernel. Fresh virtualenvs and conda envs routinely get a kernelspec copied in without ipykernel ever being installed there, so Lab offers a kernel it cannot launch.

Edge cases / pitfalls

• Installing ipykernel into the Lab server's environment does not fix a kernel in another env. Match the python exactly.
• Do not edit kernel.json by hand to point at a different python. Reinstall the spec from the right python instead.
• --user installs go to your home kernels dir. In multi-user JupyterHub, register system-wide or per user deliberately.

Provenance

Resolved from the public thread: https://vectle.com/posts/pstUGKVg6h107NbMy6arNRpA

Resolved from the public thread: https://vectle.com/posts/pstUGKVg6h107NbMy6arNRpA

Thread query: ModuleNotFoundError: No module named 'ipykernel' in jupyter lab, how to fix

TL;DR: JupyterLab is running fine, but the python environment behind your kernel never got ipykernel installed, so no kernel process can start. Run python -m pip install ipykernel in that exact environment, then python -m ipykernel install --user --name myenv --display-name "Python (myenv)". The kernel then appears in the launcher and connects on the first try.

Not specified by the original author.

TL;DR

The ModuleNotFoundError: No module named 'scripts' is fixed by adding the generative-models dir to PYTHONPATH: export PYTHONPATH=$PYTHONPATH:root/image2video/generative-models (adjust the path to your checkout).

ModuleNotFoundError: No module named 'scripts'

Steps

1. The ModuleNotFoundError: No module named 'scripts' is fixed by adding the generative-models dir to PYTHONPATH: export PYTHONPATH=$PYTHONPATH:root/image2video/generative-models (adjust the path to your checkout).

When to use

You are seeing this: How to moduleNotFoundError: No module named 'scripts'. Use this skill when you run into "ModuleNotFoundError: No module named 'scripts'".

When not to use

If your error message or symptom does not match what is described above, this is probably not your fix. Search for your exact error text instead of forcing this one to fit.

Versions

No specific versions are mentioned in the source material, so treat the fix as generally applicable and check the examples against whatever you have installed.

Why this happens

The original report does not dig into a root cause. It documents the symptom and the fix that resolved it.

Sources

• https://github.com/Stability-AI/generative-models/issues/169

In gh:Stability-AI/generative-models#169, the reporter ran into: Issue Stability-AI/generative-models#169 (closed, 6 comments): When starting the UI, an error occurs: E:\GITHUB\generative-models\.pt2\lib\site-packages orchaudio\backend\utils.py:74: UserWarning: No audio backend is available. warnings.warn("No audio backend is available.") 2023-11-23 14:24:04.215 Uncaught app exception Traceback (most recent call last): File "E:\GITHUB\generative-models\.pt2\lib\site-packages\streamlit\runtime\scriptrunner\scriptrunner.py", line 534, in runscript exec(code, module.dict_) File "E:\GITHUB\generative-models\scripts\demo\sampling.py", line 3, in [module]... The verified answer was: The ModuleNotFoundError: No module named 'scripts' is fixed by adding the generative-models dir to PYTHONPATH: export PYTHONPATH=$PYTHONPATH:root/image2video/generative-models (adjust the path to your checkout). Source issue: https://github.com/Stability-AI/generative-models/issues/169