ModuleNotFoundError: No module named 'scipy' in ComfyUI

If ComfyUI logs ModuleNotFoundError: No module named 'scipy', install the Python package scipy in the same environment that launches ComfyUI.

SciPy is a common numerical dependency. On modern Windows Python builds it normally installs from a wheel, but it is still heavier than pure-Python packages such as einops or requests. Repair it in the correct environment and verify the import before changing more packages.

In the SEO Lab portable repair chain, missing scipy appeared after Torch, TorchVision, and TorchAudio had been repaired. Installing SciPy exposed the next blocker, transformers.

.\python_embeded\python.exe -s -m pip show scipy
.\python_embeded\python.exe -s -m pip install scipy
.\python_embeded\python.exe -s -c "import scipy; print(scipy.__version__)"
.\python_embeded\python.exe -s ComfyUI\main.py --windows-standalone-build

What The Log Looks Like

ModuleNotFoundError: No module named 'scipy'

This may appear during startup, audio/video node import, preprocessing, model utilities, or custom nodes that depend on scientific Python packages.

Quick Diagnosis

Step 1: Install In The Correct Python

Windows portable:

.\python_embeded\python.exe -s -m pip install scipy

Manual venv:

python -m pip install scipy

Step 2: Verify The Import

.\python_embeded\python.exe -s -c "import scipy; print(scipy.__version__)"

Manual venv:

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

Step 3: Restart And Continue One Error At A Time

.\python_embeded\python.exe -s ComfyUI\main.py --windows-standalone-build

If the next error is No module named 'transformers', switch to the Transformers guide. That means SciPy imported successfully enough for startup to reach a later dependency.

What Not To Do

• do not install SciPy into system Python when ComfyUI uses python_embeded
• do not keep retrying a source build if a wheel should exist for your Python version
• do not downgrade NumPy blindly unless a specific compatibility error names it
• do not repair SciPy and Torch/CUDA at the same time; verify each layer

Related Guides

• Repair ComfyUI Portable Dependencies One Missing Module At A Time
• No module named 'transformers' in ComfyUI
• No module named 'torchsde' in ComfyUI
• Fix No module named errors in ComfyUI
• ComfyUI Dependency Conflicts

Source References

• Windows portable SEO Lab repair, May 18, 2026: ModuleNotFoundError: No module named 'scipy' appeared after TorchAudio repair
• Same lab ComfyUI\requirements.txt: scipy
• SciPy on PyPI