[Windows] “Open in folder” falls back to C:\ for mapped-drive/UNC project files

[lizdoddmba]

Summary

In the Windows Codex desktop app, Open in folder fails for a file in a project saved using a mapped network drive. The file preview works, but File Explorer opens at C:\ instead of the containing folder.

Environment

• Codex Windows app package: 26.810.4967.0
• Windows-native agent
• Local non-Git project
• Project saved as X:\workspace, where X: maps to a UNC network share

Steps to reproduce

1. Open a local project saved through a mapped network drive.
2. Open a generated or edited file in Codex’s file preview.
3. Choose Open → Open in folder.

Actual behavior

File Explorer opens at C:\ and does not navigate to or select the file.

Expected behavior

File Explorer opens the file’s containing folder and selects the file.

Diagnostics

• The saved project path remains the mapped-drive path.
• Both the mapped-drive and UNC forms exist and are accessible.
• Running Explorer directly with the mapped-drive file path works.
• The preview displays the file successfully.
• Based on these observations, Codex may be normalizing the preview path to UNC before invoking Explorer; this is an inference rather than a confirmed root cause.

Privacy note

The affected project contains confidential enterprise data, so no session transcript, screenshot, identifying file path, or logs are attached. A sanitized reproduction can be provided if requested.

[github-actions]

Potential duplicates detected. Please review them and close your issue if it is a duplicate.

• [Codex Desktop Windows Bug] Path normalization error with SUBST mapped drive triggers frequent crashes (no issues on macOS) #37525

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[lizdoddmba]

Issue #37525 appears related at the Windows path-normalization level, but this reproduction differs: #37525 uses a local SUBST/DOS-device mapping and reports malformed paths, file-browser failures, and crashes. This issue uses a mapped network drive backed by a UNC share and specifically reproduces Open in folder falling back to C:\, while the Codex preview and a direct Explorer invocation both succeed. I’m keeping this issue open to preserve the distinct reproduction unless maintainers confirm that it has the same root cause and should be consolidated.