Cannot execute because a node is missing the class_type property.: Node ID '#1046:935:937'

[kaiwen240]

Prerequisites

• I am running the latest version of ComfyUI
• I have searched existing issues to make sure this isn't a duplicate
• I have tested with all custom nodes disabled (see how)

What happened?

Cannot execute because a node is missing the class_type property.: Node ID '#1046:935:937'

Steps to Reproduce

How is this affecting you?

Crashes ComfyUI completely

ComfyUI Frontend Version

Cannot execute because a node is missing the class_type property.: Node ID '#1046:935:937'

Browser

Chrome/Chromium

Console Errors

Logs

Additional Context

No response

┆Issue is synchronized with this Notion page by Unito

[dosubot]

Hi @kaiwen240! I'm Dosu and I’m helping the ComfyUI_frontend team.

The error about a missing class_type property usually means a node was created or loaded without the required type information. This property is essential for nodes to function and is checked during node creation, workflow loading, and validation. Even with all custom nodes disabled, this can happen if a workflow file is corrupted, references an outdated or removed node type, or if recent changes to proxy widgets or subgraph handling affected node serialization or deserialization. Recent updates have refactored how proxy widgets and node properties are parsed and managed, which could expose issues if a workflow or node definition is malformed or incompatible with the latest frontend changes (see recent PRs, another example).

To troubleshoot: try loading a minimal workflow, re-save or rebuild the workflow from scratch, and double-check that no legacy or unsupported nodes are present. If the issue persists with all custom nodes disabled and a fresh workflow, it may be related to recent frontend changes in node property handling.

To reply, just mention @dosu.

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[christian-byrne]

This most commonly happens when one of the nodes in the workflow is not installed (custom node pack is not installed).