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LoadWorkflowWarning.outdatedVersion in ComfyUI

Partially verifiedLast verified 2026-06-22

Fix LoadWorkflowWarning.outdatedVersion and comfyui-frontend-package is not installed by updating the frontend package in the Python that starts ComfyUI.

If the workflow popup says LoadWorkflowWarning.outdatedVersion, or the terminal says comfyui-frontend-package is not installed, Failed to check frontend version, or frontend version is outdated; backend requires ... or higher, update the Python environment that actually starts ComfyUI. The warning means this ComfyUI frontend is older than the workflow, not that the graph itself is corrupt.

If the only visible text is Failed to Save Workflow Draft, save/export the workflow first and use ComfyUI Failed to Save Workflow Draft. A draft-save error can happen in the browser even when comfyui-frontend-package is not the root cause.

comfyui-frontend-package is the Python package that provides ComfyUI's browser interface.

If it is missing, outdated, or installed into the wrong Python environment, ComfyUI may start with frontend warnings, fall back to an older UI, or fail before the web interface loads.

In a real Windows portable repair, this appeared after the first missing core dependency was fixed. That means the frontend package error can be the second blocker in a damaged portable environment, not just a cosmetic UI warning.

Quick Diagnosis

What You SeeLikely CauseFirst Fix
LoadWorkflowWarning.outdatedVersion popup when opening a workflowThe workflow was saved with a newer frontend/ComfyUI than the one runningUpdate the frontend package and ComfyUI code, or open the workflow in the matching version
comfyui-frontend-package is not installedRequired package missingInstall from ComfyUI's requirements.txt
Failed to check frontend versionPython package metadata problemCheck the active Python environment
frontend version ... is outdated. backend requires ... or higherCode and frontend package versions drifted apartInstall the frontend version requested by local requirements.txt
Failed to Save Workflow Draft with no package warningBrowser workflow state failed to saveExport JSON first, then use the draft-save guide
New UI features are missing after git pullCode updated but dependencies did notRun pip install -r requirements.txt
Portable install still uses old frontendUsed system Python by accidentRun the bundled Python from the portable root
Error mentions workflow templates tooMore core packages are missingUpdate all core requirements together

The Real Log We Hit

After fixing ModuleNotFoundError: No module named 'sqlalchemy', the next startup attempt failed with:

Failed to check frontend version: No package metadata was found for comfyui-frontend-package
********** ERROR ***********
comfyui-frontend-package is not installed.
Version compatibility warning: frontend version 1.44.19 is outdated.
Backend requires 1.45.15 or higher.

That log is clear: the Python environment starting ComfyUI cannot find the package metadata. Installing the package into system Python will not help if ComfyUI is launched by python_embeded\python.exe.

What This Package Does

Older ComfyUI versions shipped more frontend files directly inside the main repository. Current ComfyUI loads the frontend from a package instead.

In the ComfyUI source, the default frontend path imports comfyui_frontend_package and serves its static directory. When the import fails, ComfyUI logs that comfyui-frontend-package is not installed.

The package is not a random plugin. It is part of the core ComfyUI runtime.

Why It Breaks After Updating

Many update problems happen because only one part of ComfyUI was updated.

For a manual install, this is incomplete:

git pull

You also need to update the packages required by that new code.

Do not run pip install -r requirements.txt blindly.

  1. Confirm which Python environment is active (where python or which python)
  2. Inspect requirements.txt — check if it pins torch, numpy, or opencv versions
  3. Install only the missing package when possible: pip install <package-name>
  4. Run pip check after installation to verify no conflicts were introduced

The official ComfyUI update guide lists comfyui-frontend-package, comfyui-workflow-templates, comfyui-embedded-docs, comfy-kitchen, and comfy-aimdo as core dependencies that may need to move with the code.

Step 1: Check the Required Version

Open:

ComfyUI/requirements.txt

Look for:

comfyui-frontend-package==...

That is the version your local ComfyUI code expects. Do not blindly install the latest frontend package if your ComfyUI code expects a specific version.

Step 2: Check the Installed Version

Run this in the same Python environment used to start ComfyUI:

python -m pip show comfyui-frontend-package

If it says the package is not found, install the specific missing package:

python -m pip install comfyui-frontend-package

Do not run pip install -r requirements.txt blindly.

  1. Confirm which Python environment is active (where python or which python)
  2. Inspect requirements.txt — check if it pins torch, numpy, or opencv versions
  3. Install only the missing package when possible: pip install <package-name>
  4. Run pip check after installation to verify no conflicts were introduced

If it shows a version lower than the one in requirements.txt, update from requirements instead of guessing a version.

Portable Windows Fix

For the GitHub Windows portable package, run from the extracted portable root: the folder that contains the run_*.bat files, python_embeded, and ComfyUI.

.\python_embeded\python.exe -s -m pip show comfyui-frontend-package

Then check the versions requested by your local ComfyUI code:

Get-Content ComfyUI\requirements.txt | Select-String "comfyui-frontend-package|comfyui-workflow-templates|comfyui-embedded-docs"

In the repaired lab environment, the matching fix was:

.\python_embeded\python.exe -s -m pip install "comfyui-frontend-package==1.42.15" "comfyui-workflow-templates==0.9.63" "comfyui-embedded-docs==0.4.4"

Use the versions from your own ComfyUI\requirements.txt if they differ.

Do not run pip install from a random system terminal unless you know it points at the portable Python. Installing into the wrong Python is the most common reason the error keeps coming back.

If the frontend package error appears after other core missing-package errors, read Repair Broken ComfyUI Portable Dependencies Without Reinstalling Torch before running broad package updates.

For ComfyUI Desktop or another managed launcher, use the app's own terminal, updater, or environment tools instead of copying the portable python_embeded path.

Manual Install Fix

Activate your virtual environment first:

.\venv\Scripts\activate

Then update from the ComfyUI folder:

cd ComfyUI
git pull
python main.py

Do not run pip install -r requirements.txt blindly.

  1. Confirm which Python environment is active (where python or which python)
  2. Inspect requirements.txt — check if it pins torch, numpy, or opencv versions
  3. Install only the missing package when possible: pip install <package-name>
  4. Run pip check after installation to verify no conflicts were introduced

If you use Conda, activate the Conda environment before installing requirements.

What Not to Do

Avoid these shortcuts:

  • do not install frontend packages into system Python while ComfyUI uses a venv
  • do not upgrade only comfyui-frontend-package while ignoring other core packages
  • do not run every custom node requirements.txt after fixing the frontend
  • do not delete ComfyUI before reading the first error in the log
  • do not mix stable and nightly update paths without knowing which one you want

If It Says "Not Found in requirements.txt"

If a tool says comfyui-frontend-package not found in requirements.txt, check three things:

  1. You are looking at the correct ComfyUI/requirements.txt.
  2. The ComfyUI code was actually updated.
  3. You are not running from an old fork, old zip, or partial copy.

For a Git install:

git status
git pull

If Git says the folder is not a repository, use ComfyUI Won't Update.

How Wonderful Launcher Helps

Frontend package errors are usually environment errors, not workflow errors. Wonderful Launcher helps when you need to:

  • keep several ComfyUI environments separate
  • preserve a working environment before updating packages
  • collect startup logs that show the active frontend version
  • recover from custom node installs that changed core dependencies

If your environment breaks every time you update, read ComfyUI Dependency Conflicts before installing more packages.

Related Guides

  • ComfyUI Failed to Save Workflow Draft
  • ComfyUI "clean library entry point is missing" Fix
  • Repair Broken ComfyUI Portable Dependencies Without Reinstalling Torch
  • ModuleNotFoundError: No module named 'sqlalchemy' in ComfyUI
  • ComfyUI Won't Update
  • ComfyUI Dependency Conflicts
  • ComfyUI Startup Failed
  • Install ComfyUI Custom Nodes

Source References

  • Official ComfyUI update guide
  • ComfyUI frontend management source
  • ComfyUI command-line arguments
  • Windows portable repair lab, May 18, 2026: comfyui-frontend-package is not installed was resolved by installing the package versions requested in local ComfyUI\requirements.txt

Start free with Wonderful Launcher if this affects your real ComfyUI environment. It keeps launcher-native repair, task logs, and runtime checks in one place; credits are only for image generation and metered tools.

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Table of Contents

Quick Diagnosis
The Real Log We Hit
What This Package Does
Why It Breaks After Updating
Step 1: Check the Required Version
Step 2: Check the Installed Version
Portable Windows Fix
Manual Install Fix
What Not to Do
If It Says "Not Found in requirements.txt"
How Wonderful Launcher Helps
Related Guides
Source References