ComfyUI ModuleNotFoundError / "No module named" — custom node won't import
Also seen as: "ModuleNotFoundError", "No module named", "ImportError", "cannot import"
Direct answer
How do I fix "ModuleNotFoundError"?
A ModuleNotFoundError at ComfyUI startup almost always means a custom node's Python dependency didn't install — the node folder is there, but a package it imports is missing.
Key facts
- iA custom node's requirements.txt never ran (headless installs skip it).
- iA from-source build (sam2, llama-cpp-python, insightface) failed or timed out.
- iPython/torch version mismatch — a wheel built for a different version.
Next step
- 1Reinstall the node's requirements: pip install -r custom_nodes/<node>/requirements.txt.
- 2For from-source packages, use --prefer-binary and a longer build timeout, or a prebuilt wheel.
- 3Paste the workflow into a checker that resolves each node to its repo + install command before you deploy.
- 4Match torch/CUDA versions to what the node was built against.
If that didn't fix it
- Reinstalling the node folder won't help if the missing package is a system build dependency.
Not sure this workflow will run before you rent a GPU?
Paste your ComfyUI workflow JSON into the free checker — it flags known dependencies and an estimated hardware requirement. It does not run the workflow, verify GPU capacity or judge output quality. No signup.
Other ComfyUI errors
Frequently Asked Questions
What causes "ModuleNotFoundError" in ComfyUI?
A custom node's requirements.txt never ran (headless installs skip it).
How do I fix "ModuleNotFoundError"?
Reinstall the node's requirements: pip install -r custom_nodes/<node>/requirements.txt. For from-source packages, use --prefer-binary and a longer build timeout, or a prebuilt wheel.