KJ Nodes Dead in the Water

[Metairieman55]

I am a ComfyUI Portable user for years now on the following system since Dec 2025:
:: HARDWARE INFO ::

System RAM: 63 GB
GPU Model: NVIDIA GeForce RTX 5090
Video VRAM: 32 GB

:: SOFTWARE & VERSIONS ::

ComfyUI : v0.29.0

Windows long path support is Enabled

Python : 3.12
PyTorch : 2.10
CUDA Core : 13.0

NVIDIA-drv: 610.47

The issue I've been confronting is specifically with ALL LTX2.3 workflows using the KJ Nodes for the VAE Loader especially. Manager install, CMD install, update, version change, etc., nothing seems to "find" those components and even the ComfyUI Templates won't work no less others' workflows. I regularly update CUI and the nodes, also. I can run Wan2.2 workflows without a hitch all day but can't get LTX2.3 to cooperate.

Any ideas? Could it be a Python version clash or something similar?

[direwind]

Python Version
3.13.12 (main, Feb 12 2026, 00:38:53) [MSC v.1944 64 bit (AMD64)]

PyTorch Version
2.13.0+cu130 and running perfectly for ltx 2.3 can even do 40 second render without craziness in around 8m. have you tried a clean install?

[vavo]

This looks like a KJNodes import failure, not evidence of a Python 3.12 clash. VAELoaderKJ is still registered by current KJNodes, while its LTX-specific nodes are imported in a guarded block. When that block fails, startup logs the exact message KJNodes: LTXV nodes could not be imported followed by the real exception.

Start ComfyUI from the console and find the first KJNodes traceback during startup. That exception is the useful part; the red missing-node boxes in the workflow are only the aftermath.

For Portable, install KJNodes requirements with Portable's embedded Python, not the system Python:

python_embeded\python.exe -m pip install -r ComfyUI\custom_nodes\ComfyUI-KJNodes\requirements.txt

Then update ComfyUI core and KJNodes together and restart. KJNodes' current LTX module imports APIs from current ComfyUI core, so mixing an old core with a newer custom-node checkout can make the whole LTX block disappear.

After restart, http://127.0.0.1:8188/object_info/VAELoaderKJ should return the node definition. If it returns nothing, paste the first KJNodes startup traceback..

or try using my comfyui skill; https://github.com/vavo/comfyui-codex