Windows sandbox apply_patch cannot update existing files in VS Code extension: helper_unknown_error applying deny-read ACLs

Open 💬 2 comments Opened Jul 12, 2026 by Lakshay-24
💡 Likely answer: A maintainer (github-actions[bot], contributor) responded on this thread — see the highlighted reply below.

What version of the IDE extension are you using?

Codex extension for Visual Studio Code on Windows. Exact extension version can be added if needed.

Which IDE are you using?

Visual Studio Code on Windows.

What platform is your computer?

Windows host with an NTFS checkout.

Workspace path:

C:\Users\laksh\Reels Maker Stack\OpenMontage

What issue are you seeing?

In the Codex VS Code extension, apply_patch fails when trying to update an existing tracked file because the Windows sandbox helper cannot apply deny-read ACLs.

Full error:

apply_patch verification failed:
Failed to read file to update
C:\Users\laksh\Reels Maker Stack\OpenMontage\apps\creator-studio-web\lib\jobExecution.ts:
fs sandbox helper failed with status exit code: 1:
windows sandbox failed:
helper_unknown_error: apply deny-read ACLs

The failure happens before the patch is applied. No repository file is modified.

This appears to be a failure in the Codex Windows sandbox ACL helper, rather than Git or the repository's ordinary file permissions.

Steps to reproduce

  1. Open an existing Git repository stored on NTFS in the Codex VS Code extension on Windows.
  2. Ask Codex to modify an existing tracked file using apply_patch.
  3. apply_patch fails before reading or updating the file with:
helper_unknown_error: apply deny-read ACLs

Diagnostic details

  • Normal sandboxed PowerShell reads succeed.
  • git status succeeds.
  • git rev-parse succeeds.
  • Unsandboxed/elevated reads succeed.
  • apply_patch can sometimes create new files.
  • apply_patch cannot read or update an existing tracked file.
  • Both absolute and workspace-relative patch paths fail.
  • icacls /reset did not fix it.
  • Re-enabling inherited permissions did not fix it.
  • Restarting Codex did not fix it.
  • Rebooting Windows did not fix it.
  • The workspace is under a path containing spaces, but both absolute and relative patch paths fail.
  • The checkout is on NTFS.

Expected behavior

apply_patch should be able to read and update existing tracked files inside the selected writable VS Code workspace.

Actual behavior

The sandbox ACL helper fails before patch verification, so apply_patch cannot modify existing files even though ordinary reads and Git commands work.

Related issues

There are similar reports for the Windows Codex app/CLI where apply_patch can create files but cannot update or delete existing files, including #32121 and #31229. This report is specifically for the Codex VS Code extension.

View original on GitHub ↗

2 Comments

github-actions[bot] contributor · 1 month ago

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

  • #31229
  • #32121

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topeguipo · 16 days ago

I can reproduce this issue in the Codex Windows desktop app as well.

Environment

Windows 11
Codex desktop app
Existing Git repository on NTFS
Settings → General → Full access enabled

Reproduction

Normal Git operations succeed:
git status --short
git branch --show-current
git rev-parse HEAD
Tested with an isolated untracked .codex-write-check file so no application source needed to be modified.
Attempting to remove/modify the marker using the standard apply_patch mechanism fails.
Retried apply_patch twice with the same result.

Codex reports:

Windows sandbox helper failed while applying its deny-read ACLs.

This still occurs with Full access enabled.

I did not modify Windows ACLs, use icacls, take ownership of files, or use an alternative filesystem deletion method as a workaround.

The repository remains readable and Git commands work normally; the failure appears specifically in the Windows sandbox ACL setup used by apply_patch.

This currently blocks normal Codex editing of an existing Windows repository.