ComfyUI-Manager: ModuleNotFoundError: No module named 'comfy' (fix)

ModuleNotFoundError: No module named 'comfy' from ComfyUI-Manager means Manager code ran in a Python process that cannot see your ComfyUI folder. We reproduced it with comfyui_manager 4.2.2 and fixed it three ways.

1. The error

ComfyUI-Manager 4.x is a pip package (comfyui_manager, version 4.2.2 here). Importing it from a Python process that is not running inside the ComfyUI folder:

Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "venv/lib/python3.11/site-packages/comfyui_manager/__init__.py", line 6, in <module>
    from comfy.cli_args import args
ModuleNotFoundError: No module named 'comfy'

Line 6 of the package's __init__.py is from comfy.cli_args import args. comfy is not something pip installs: it is the comfy/ folder inside your ComfyUI checkout. Python only finds it when that folder is on sys.path. Running python main.py puts the ComfyUI folder there automatically (we also ran main.py from a different working directory and it still started), so the error comes from starting Manager code some other way: a standalone script, python -c, a notebook, or a tool that imports comfyui_manager outside ComfyUI. The same import comfyui_manager worked when run from the ComfyUI folder and when PYTHONPATH pointed at it.

2. Fix: let ComfyUI load Manager

Recent ComfyUI (v0.37.0 here) ships a manager_requirements.txt (here pinning comfyui_manager==4.2.2) and loads Manager itself with a flag. Without the package installed, python main.py --enable-manager printed:

[WARNING] 

To use the `--enable-manager` feature, the `comfyui-manager` package must be installed first.
command:
	venv/bin/python -m pip install -r ComfyUI/manager_requirements.txt

Run that command with the Python that runs main.py, then start ComfyUI with --enable-manager again:

cd ComfyUI
python -m pip install -r manager_requirements.txt
python main.py --enable-manager

[INFO] [START] ComfyUI-Manager
[ComfyUI-Manager] Using GitPython backend
[INFO] [ComfyUI-Manager] network_mode: public
[INFO] [ComfyUI-Manager] All startup tasks have been completed.

3. cm-cli: set COMFYUI_PATH

The package also installs a cm-cli command. Without the environment variable it stops with:

cm-cli: environment variable 'COMFYUI_PATH' is not specified.

cm-cli appends COMFYUI_PATH to sys.path, which is how it finds comfy. Point it at the ComfyUI folder (the one containing main.py):

COMFYUI_PATH=/path/to/ComfyUI cm-cli show installed

FETCH DATA from: ComfyUI/user/__manager/cache/1514988643_custom-node-list.json [DONE]
FETCH DATA from: ComfyUI/user/__manager/cache/1514988643_custom-node-list.json [DONE]
[    ENABLED    ]  ComfyUI InstantID (Native Support)                 
ComfyUI_InstantID              (author: cubiq               ) [UNKNOWN]
[    ENABLED    ]  ComfyUI-GGUF                                       
ComfyUI-GGUF                   (author: city96              ) [UNKNOWN]

On Windows: set COMFYUI_PATH=C:\path\to\ComfyUI first. One more trap: comfyui_manager 4.2.2 imports aiohttp but does not list it as a dependency, so in a fresh venv without ComfyUI's own requirements cm-cli failed one step earlier:

Traceback (most recent call last):
  File "venv/bin/cm-cli", line 10, in <module>
    sys.exit(main())
             ^^^^^^
  File "venv/lib/python3.11/site-packages/cm_cli/__init__.py", line 2, in main
    from .__main__ import main as _main
  File "venv/lib/python3.11/site-packages/cm_cli/__main__.py", line 35, in <module>
    from comfyui_manager.common import manager_util
  File "venv/lib/python3.11/site-packages/comfyui_manager/__init__.py", line 3, in <module>
    from aiohttp import web
ModuleNotFoundError: No module named 'aiohttp'

Installing into the same venv as ComfyUI avoids that (aiohttp is in ComfyUI's requirements.txt); otherwise pip install aiohttp.

Related: ComfyUI-Manager: No module named 'git' · ComfyUI-Manager: No module named 'toml' · cm-cli.py: No module named 'utils' (git-clone Manager) · ComfyUI-Manager: Bad git executable · ComfyUI: No module named 'insightface' · ComfyUI: No module named 'av'

Written with AI assistance. Measured on 2026-10-24 on Linux, CPython 3.11.17: ComfyUI v0.37.0, comfyui_manager 4.2.2 from PyPI (with and without ComfyUI on sys.path), cm-cli with and without COMFYUI_PATH. Output pasted unedited except shortened paths. PlainTables is our extension; ComfyUI and ComfyUI-Manager are free.