Spandrel is installed but the model will not load: check architecture support

Installation is only the first checkpoint

Spandrel detects and loads a documented subset of PyTorch model architectures; it does not support every PyTorch checkpoint. Its README lists architectures and marks those available only through spandrel_extra_arches with +. That extra package contains architectures with more restrictive licenses, so installation and intended use need separate checks. Spandrel README

python -c "import sys; print(sys.executable); import spandrel; print(spandrel.__file__)"

Run this under the same interpreter that starts ComfyUI, then record the caller node revision and the model publisher, original release, exact file and revision. The README lists .pth, some .pt and .ckpt, and .safetensors for supported architectures; the extension alone does not prove architecture support. Supported file types

A missing import calls for a package/interpreter check. An UnsupportedModelError or unrecognized state dict calls for the exact architecture and installed registry to be checked against that release; it is not proof that the file is corrupt. The upstream contribution guide describes registry detection from weight keys. Unexpected keys or shapes also require file-identity and structure checks. Renaming a file does not change its architecture. Architecture detection

If the required architecture is marked +, the upstream example imports spandrel_extra_arches and calls spandrel_extra_arches.install() before using ModelLoader; having the extra distribution installed does not by itself prove that the calling node registers it. Confirm that node integration and the model/architecture licenses before changing the environment. Compare with a known-source model supported by the selected release. Record import, architecture recognition, model load and output separately; do not treat a model-specific failure as a reason to reinstall everything. Extra-architecture setup

Related checks

• Kornia import errors: check the base package, Torch and optional extras
• Missing safetensors package or unreadable weights? Diagnose them separately

Sources and English text reviewed 2026-09-26. No package installation, model load, ComfyUI run or GPU reproduction. The checks are editorial guidance, not a diagnosis of your model.