ComfyUI CUDA out of memory
Reduce VRAM pressure using the failing stage, resolution and batch size.
Checklist → verify → recordComfyUI error library
Find the relevant exception, follow a specific checklist and verify the result.
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ComfyUI missing custom nodes
Identify unavailable node classes without installing an unrelated package.
Checklist → verify → recordComfyUI model not found
Check loader choices, model locations and compatible model families.
Checklist → verify → recordComfyUI custom node import failed
Find the first import exception in the Python environment ComfyUI actually uses.
Checklist → verify → recordComfyUI tensor shape mismatch
Trace incompatible dimensions and model components before changing random settings.
Checklist → verify → recordComfyUI prompt validation failed
Separate missing inputs and invalid selections from runtime exceptions.
Checklist → verify → recordComfyUI failed to connect to server
Determine whether the browser, local server or external provider is failing.
Checklist → verify → recordComfyUI KSampler error: trace the cause
Use the root exception to distinguish sampling, models, memory and custom nodes.
Checklist → verify → recordStart with the complete error
Match the final exception and failing stage, not only the last node name. A loader failure, graph validation rejection and GPU allocation error are different investigations. Run local checks first; make one reversible change to a copy and verify it in ComfyUI.
Inspect a log · Check a workflow · Start from a documented template