Troubleshooting1 min read
simpleeval: distinguish a missing module from an invalid expressionLog keyword: No module named simpleeval
Check the dependency first, then the expression and allowed operations exposed by the node.
THE LIBRARY / ERRORS
Troubleshooting
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Troubleshooting1 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.
Troubleshooting1 min read
SciPy, einops and torchsde: distinguish missing imports from failed operationsLog keyword: No module named scipy
Keep the precise import and operation errors instead of treating every scientific-library failure as an install issue.
Troubleshooting1 min read
No module named av: why installing FFmpeg may not fix the Python importLog keyword: No module named av
Check PyAV, its linked libraries and an external FFmpeg executable as separate dependencies.
Troubleshooting1 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.
Troubleshooting1 min read
Kornia import errors: check the base package, Torch and optional extrasLog keyword: No module named kornia
Distinguish a missing base package from an optional feature dependency before changing Torch.
Troubleshooting1 min read
ONNX Runtime imports, but GPU execution fails: check providers and sessionsLog keyword: No module named onnxruntime
Separate package discovery, runtime providers and the session that actually executes your model.
Troubleshooting1 min read
Fix cv2 imports without stacking OpenCV distributionsLog keyword: No module named cv2
Identify the installed OpenCV flavor before investigating missing modules or native-library loading.
Troubleshooting2 min read
FFmpeg audio contains NaN or Inf: trace effects and decoding upstreamLog keyword: Input contains (near) NaN/+-Inf
A codec rejecting nonfinite samples is not necessarily missing. Follow the audio entering it back through processing and decoding.
Troubleshooting2 min read
Core updated but nodes or templates are missing: check component versions separatelyLog keyword: workflow templates
Core source, Desktop shell, frontend package, templates and custom nodes are not one indivisible version. An update can leave some components behind.
Troubleshooting2 min read
Cannot connect to 127.0.0.1:8188: locate the running ComfyUI serviceLog keyword: Connection refused
localhost identifies the device making the request. Its meaning differs across a browser, phone, container, notebook and remote server.
Troubleshooting2 min read
Dependency cycle detected: trace the reported node IDs through the graphLog keyword: Dependency cycle detected
A normal data-dependency loop prevents a valid execution order. This is different from a supported loop/control-flow node with explicitly defined semantics.
Troubleshooting2 min read
Custom validation failed: read the node's own error detailsLog keyword: Custom validation failed for node
The generic banner says the node's validation rejected an input or raised an exception. It does not identify whether the real cause is a missing file, invalid media or code incompatibility.
Troubleshooting2 min read
Numeric input validation failed: use the node's actual types and boundsLog keyword: invalid_input_type
Conversion failures and values outside min/max are related input-validation cases. Fix the field definition rather than silently clipping every value.
Troubleshooting2 min read
Bad linked input: represent API connections with a source node and output slotLog keyword: Bad linked input
An inputs list may be interpreted as a link rather than a literal array. Inspect serialization before assuming every JSON list will reach a node unchanged.
Troubleshooting2 min read
Return type mismatch: inspect the source output slot and destination inputLog keyword: Return type mismatch between linked nodes
IMAGE, LATENT, MODEL and CONDITIONING have different roles. A drawable connection or similar socket color is not sufficient evidence of a valid interface.
Troubleshooting2 min read
Required input is missing: identify the exact node and fieldLog keyword: Required input is missing
The backend found a missing required input before execution. Use the reported node and field to repair that specific gap before investigating further failures.
Troubleshooting2 min read
Node has no class_type: distinguish API export errors from missing registrationLog keyword: has no class_type
An API execution node needs class_type. The same missing_node_type category may also report a class that exists in the request but is unknown to the backend, so read message and extra_info together.
Troubleshooting2 min read
Float8 is unsupported on MPS: distinguish stored weights from compute dtypeLog keyword: Float8_e4m3fn
Locate whether the failure happens during weight loading, dequantization or an operation. A file's FP8 label alone does not describe every possible quantized execution path.
Troubleshooting2 min read
Windows Overlapped operation errors in Manager: check the documented event-loop optionLog keyword: Overlapped Object has pending operation at deallocation
Use this path only when the complete traceback matches the relevant Windows asyncio/Manager failure. An event-loop error may also follow an earlier network exception.
Troubleshooting2 min read
Manager cannot find Git: check the environment that launches ComfyUILog keyword: Bad git executable
Git may work in one terminal but remain unavailable to a previously started launcher, service or container. Confirm the caller's executable search path.
Troubleshooting2 min read
Manager security policy blocks an action: confirm authorization and scopeLog keyword: This action is not allowed with this security level configuration
A blocked installation or command can be deliberate policy enforcement rather than corruption. Determine which action was refused and who is permitted to change it.
Troubleshooting2 min read
pip certificate verification failed: repair trust without disabling TLSLog keyword: CERTIFICATE_VERIFY_FAILED
Diagnose the failing hostname, certificate chain and interpreter before treating HTTPS verification as an inconvenience to bypass.
Troubleshooting2 min read
ComfyUI Manager button missing: distinguish UI changes from load failuresLog keyword: ComfyUI-Manager
Desktop, newer Manager interfaces and legacy installations do not necessarily expose Manager in the same place or install it in the same way.