Troubleshooting2 min read
Spandrel is installed but the model will not load: check architecture supportLog keyword: No module named spandrel
Separate the library import from architecture support and the identity of the weights.
THE LIBRARY / ERRORS
Troubleshooting
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Troubleshooting2 min read
Transformers errors: separate imports, API changes and model downloadsLog keyword: No module named transformers
Locate the failing stage before changing Transformers, model files or network settings.
Troubleshooting2 min read
Missing safetensors package or unreadable weights? Diagnose them separatelyLog keyword: No module named safetensors
Distinguish the Python library from the weight file before reinstalling packages or downloading models again.
Troubleshooting3 min read
llama_cpp failures: distinguish installation, native builds and model loadingLog keyword: No module named llama_cpp
Check the distribution and backend before treating a compiler error or model error as a missing import.
Troubleshooting3 min read
Nunchaku still fails after installation: align the node, wheel and modelLog keyword: No module named nunchaku
Check the wheel tags and keep the ComfyUI extension, native library and model separate.
Troubleshooting3 min read
InsightFace installation or initialization fails: separate packages from FaceID assetsLog keyword: No module named 'insightface'
Missing insightface, failed wheel builds and initialization errors require different checks: interpreter, native build, execution backend and model files.
Troubleshooting3 min read
IPAdapter model not found: unified presets and manual loaders use different rulesLog keyword: IPAdapter model not found.
A downloaded IPAdapter file can exist on disk without satisfying a unified loader's preset matching. Identify the loader before renaming or relocating files.
Troubleshooting3 min read
CLIP Vision missing or incompatible: it is not the prompt's text encoderLog keyword: ClipVision model not found.
Reference-image workflows need a vision encoder with the expected architecture. Distinguish it from the object feeding CLIPTextEncode.
Troubleshooting3 min read
Dragging an image does not restore a workflow: verify that metadata survivedLog keyword: No workflow found
A displayed result, screenshot or resaved image may not contain recoverable workflow data. This alone does not indicate a broken import function.
Troubleshooting3 min read
FFmpeg not found: test the executable in ComfyUI's process environmentLog keyword: ffmpeg not found
Determine whether the missing item is FFmpeg itself, an input file or an encoder. The appearance of ffmpeg in a log does not justify reinstalling the whole video stack.
Troubleshooting3 min read
DLL load failed: identify the native extension instead of downloading loose DLLsLog keyword: DLL load failed
The named Python module can depend on another missing or incompatible runtime library. Native import failure is different from a top-level Python package simply being absent.
Troubleshooting3 min read
VHS output is nearly silent: inspect audio dtype before increasing gainLog keyword: VHS_VideoCombine
This case-led guide concerns a reported fp16-intermediate scenario, not every silent track. First establish whether audio exists and is valid before composition.
Troubleshooting2 min read
Prompt has no outputs: provide an actual execution endpointLog keyword: Prompt has no outputs
A graph of loaders and intermediate calculations does not necessarily specify an output to execute. Locate a valid result endpoint rather than the visually rightmost node.
Troubleshooting2 min read
Queue finishes quickly but no new file appears: check cache and output locationLog keyword: execution_cached
A fast completion can involve cached execution, a preview-only endpoint, temporary storage or a client misreading events. It is not automatically a failed generation.
Troubleshooting2 min read
Address already in use: identify the process before stopping anythingLog keyword: Address already in use
Repeatedly starting ComfyUI can collide with an existing healthy instance. A port conflict is not permission to terminate every Python process.
Troubleshooting2 min read
A GGUF file will not load: match the architecture and the specialized loaderLog keyword: UnetLoaderGGUF
GGUF is a container format, not a guarantee that an arbitrary chat-model file can serve as a diffusion model or text encoder in a particular ComfyUI node.
Troubleshooting2 min read
No module named yaml, PIL or pydantic_settings: check the distribution nameLog keyword: No module named yaml
Match the import name to its distribution before changing the Python environment that runs ComfyUI.
Troubleshooting2 min read
aiohttp and requests: a missing library is not a connection failureLog keyword: No module named aiohttp
Check library availability before investigating DNS, TLS, HTTP responses or timeouts.
Troubleshooting2 min read
Manager cannot load the node list: investigate retrieval before reinstalling nodesLog keyword: Failed to get custom node list
Distinguish registry retrieval, search filters, installed code and Python imports.
Troubleshooting2 min read
ComfyUI workflow save failed: preserve the canvas before troubleshootingLog keyword: Failed to save workflow
Preserve an export before investigating draft storage, file downloads or API-format confusion.
Troubleshooting2 min read
ComfyUI Failed to fetch: identify the request before reinstallingLog keyword: Failed to fetch
Locate the failing endpoint and distinguish the backend, logs, registry and workflow-save requests.
Troubleshooting2 min read
Float, Half and BFloat16 mismatch: trace the failing operationLog keyword: mat1 and mat2 must have the same dtype
A dtype failure differs from a shape or device failure. Start with the traceback and incompatible operand types; a KSampler error alone does not identify the component that caused them.
Troubleshooting2 min read
Blank ComfyUI screen after an extension update: separate frontend and backend failuresLog keyword: Failed to fetch dynamically imported module
The Python server may still be running while the canvas fails. Distinguish static assets, JavaScript extensions and an absent backend before reinstalling unrelated models.
Troubleshooting2 min read
Black images or invalid colors: separate sampling, VAE and display failuresLog keyword: invalid value encountered in cast
Compare the saved artifact with the preview before diagnosing a black image. A black preview and genuinely invalid output pixels are different observations.