What it means
The package folder exists in custom_nodes, but when ComfyUI tried to import it at startup the import raised an exception — most often a missing Python dependency (ModuleNotFoundError) or a version incompatibility. The node therefore never registers, and any workflow using it will also report the node type as not found.
The authoritative detail is in the server console, not the browser: the startup log prints the traceback for each failed import, which names the exact missing module or conflicting version.
Common causes
- The node’s requirements.txt was never installed into the active environment.
- A dependency version conflicts with another custom node or with ComfyUI itself.
- Packages were installed into a different Python environment than the one running ComfyUI.
- The node needs a build step or a specific torch/CUDA version.
How to fix it
- 1
Read the traceback in the server console
Find the "IMPORT FAILED" line for the node in the startup log; the traceback underneath names the missing module or version conflict.
- 2
Install the node’s requirements
From the node’s folder, install its requirements.txt into the same Python environment that runs ComfyUI (activate that environment first so packages land in the right place).
- 3
Try the Manager’s fix action
ComfyUI Manager offers a "Try Fix" / reinstall action per custom node that re-runs its dependency install.
- 4
Resolve version conflicts
If two nodes require incompatible versions of a package, check each repo’s notes for a compatible pin, or isolate the environment.
Recording the environment a workflow ran in — the packages and versions present — turns "it worked on that machine" into something you can actually reproduce.
Frequently asked questions
Frequently Asked Questions
Quick answers to the most common questions.
Related errors
Make every ComfyUI run reproducible
Numonic captures the full workflow behind each ComfyUI generation — models, samplers, seeds, prompts, and custom nodes — so a setup that finally works is one you can find and rebuild, not re-debug.