How to Fix Custom Node requirements.txt Not Installed in ComfyUI

If a ComfyUI custom node shows IMPORT FAILED in the startup log because of a ModuleNotFoundError, the most common cause is that the node's requirements.txt was never installed.

Cloning or downloading a custom node into custom_nodes/ only copies the code. The Python packages that code depends on must be installed separately.

.\python_embeded\python.exe -s -m pip install -r ComfyUI\custom_nodes\<node-name>\requirements.txt
.\python_embeded\python.exe -s ComfyUI\main.py --windows-standalone-build

What the error looks like

IMPORT FAILED: ComfyUI-ExampleNode
Traceback (most recent call last):
  File "...\custom_nodes\ComfyUI-ExampleNode\__init__.py", line 4, in <module>
    import somepackage
ModuleNotFoundError: No module named 'somepackage'

The node folder exists in custom_nodes/, but the import fails because somepackage is not installed.

Why it happens

• Manual git clone without pip install: You cloned the node repo but forgot to install its requirements
• ComfyUI Manager partial install: Manager may have cloned the repo but the requirements install step failed silently
• Environment was rebuilt: You reinstalled ComfyUI or updated the portable package, wiping previously installed packages
• Wrong Python used for install: Requirements were installed into system Python, not ComfyUI's embedded Python
• No requirements.txt: Some nodes list dependencies only in their README, not in a requirements file

Step-by-step fix

Step 1: Find the failing node

Check the ComfyUI startup log for IMPORT FAILED lines. The line tells you which custom node folder failed and which module is missing.

Step 2: Check if requirements.txt exists

dir ComfyUI\custom_nodes\<node-name>\requirements.txt

If it exists, proceed to Step 3. If not, check the node's README on GitHub for manual dependency instructions.

Step 3: Read the requirements file before installing

type ComfyUI\custom_nodes\<node-name>\requirements.txt

Look for red flags:

If the file looks safe, proceed. If it contains torch or other core packages, consider installing only the actually missing packages manually instead.

Step 4: Install the requirements

For Windows portable:

.\python_embeded\python.exe -s -m pip install -r ComfyUI\custom_nodes\<node-name>\requirements.txt

For a manual venv:

python -m pip install -r custom_nodes/<node-name>/requirements.txt

Step 5: If the requirements file would break your environment

Instead of installing everything, install only the specific missing package:

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

This is safer when the requirements file includes core packages like torch.

Step 6: Verify

Restart ComfyUI and check that the IMPORT FAILED line is gone:

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

Batch-installing requirements for all custom nodes

If multiple nodes have missing requirements, you can install them all, but this carries more risk:

for /d %d in (ComfyUI\custom_nodes\*) do if exist "%d\requirements.txt" .\python_embeded\python.exe -s -m pip install -r "%d\requirements.txt"

Warning: Running this blindly can cause dependency conflicts. It is safer to install requirements one node at a time, checking for errors between each install.

When not to run pip install blindly

• Always read requirements.txt before running it — some node authors pin aggressive torch versions
• If pip check shows conflicts after installing, do not keep installing more requirements. Fix the conflict first
• If a requirements file is very old, the pinned versions may not work with your current Python or PyTorch
• Consider using --no-deps for individual packages if you only need the package itself, not its dependency tree

How Wonderful Launcher can help

Wonderful Launcher helps detect custom nodes with uninstalled requirements and assists with installing them safely. It checks for conflicts before installing and helps prevent requirements from breaking your core PyTorch setup.

Download Wonderful Launcher — it's free and helps manage custom node dependencies.

Related errors

• ComfyUI Plugin Import Failed
• ComfyUI Dependency Conflicts
• ComfyUI Custom Nodes Broke Environment
• Install Custom Nodes
• Plugin Missing Module Warning: When It Is Safe to Ignore

Source References

• ComfyUI GitHub
• ComfyUI Documentation
• pip Documentation