[Windows Desktop][Visualize] Native C:\ visualization path renders as missing-image placeholder

What version of the Codex App are you using?

Codex Desktop for Windows.

• Microsoft Store package: OpenAI.Codex_26.818.5229.0_x64
• Executable file/product version: 151.0.7922.170
• Bundled Visualize plugin: 1.0.22

What subscription do you have?

Not relevant to this local renderer reproduction; not disclosed.

What platform is your computer?

Windows x64, version 25H2, build 26200.9168.

The task runs natively in Windows PowerShell. WSL is not involved.

What issue are you seeing?

An inline visualization referenced with an absolute native Windows path inside the thread-scoped visualization root does not render in Codex Desktop. The response surface shows a generic missing-image/asset placeholder instead of the visualization or an actionable error.

The fragment was written to the declared writable location:

C:\Users\<user>\.codex\visualizations\YYYY\MM\DD\<thread-id>\redisenio-dosificador.html

The response referenced that same absolute native path through the Visualize content reference.

Observed evidence:

• The fragment exists at the referenced path and is readable.
• Fragment size: 14,816 bytes.
• JavaScript syntax validation passed.
• The bundled renderer script produced a standalone HTML file of 52,927 bytes from the same fragment.
• A native headless browser can display the local source after wrapping.
• The inline surface still displays only the placeholder.
• The behavior occurred repeatedly in the same task with more than one attempted visualization delivery.

What steps can reproduce the bug?

1. Open Codex Desktop on Windows with a native PowerShell execution environment.
2. Create an HTML visualization fragment under the provided thread-scoped writable root:
   C:\Users\<user>\.codex\visualizations\YYYY\MM\DD\<thread-id>\example.html.
3. Confirm that the file exists and is readable.
4. Emit the Visualize content reference using that exact absolute C:\... path.
5. Observe that the conversation displays a generic image/asset placeholder rather than the visualization.
6. Reopen the task or repeat with another visualization in the same valid root; the content remains unavailable.

What is the expected behavior?

Codex Desktop should read and display visualization fragments referenced by an absolute native Windows path that is inside the task's declared thread-scoped visualization root.

If loading or parsing fails, the placeholder should remain visible and show an actionable error containing the sanitized requested path, resolved path, and failure stage.

What is the actual behavior?

The visualization is not shown. A generic missing-image/asset placeholder is displayed without a useful diagnostic, although the referenced source exists locally.

Additional information

This is adjacent to, but distinct from:

• #40100, which reproduces when a WSL /mnt/c/... path is handled with Windows semantics. This report already uses a native C:\... path and does not involve WSL.
• #32054, which reports a workspace-level versus home-level visualization-directory mismatch. This report already stores the fragment under the user's home-level .codex\visualizations\... directory.

The user name, thread identifier, project path, and visualization contents are intentionally omitted.

Reproduce the failure in Codex Desktop on Windows using an HTML fragment under the thread-scoped visualization root and an absolute C:\ path. Trace the Visualize content-reference handling and Windows path resolution; done means the existing fragment renders, or failures show an actionable diagnostic with the sanitized and resolved paths and failure stage.