Windows Codex App: all local child-process tools hang with empty output after update and reboot

What version of the Codex App are you using?

26.707.51957

The app reports bundled workspace dependencies version 26.709.11516 on 2026-07-12.

Platform

Windows, x64. Codex desktop app. Workspace: a normal local Git repository at C:\GitHub\Aurora.

Summary

After a recent Codex Windows app update, all local child-process execution from the agent hangs and returns no stdout/stderr. This persists after a full Windows reboot.

The failure is not repository-specific and occurs both inside and outside the sandbox.

Minimal reproduction

1. Open a local workspace in the Codex Windows app.
2. Ask the agent to run:

``powershell
Write-Output ('CODEX_PROBE ' + (Get-Date -Format o))
Get-Location
``

1. Run it with a 10-second timeout.

Actual result:

• The command remains "Script running" beyond the timeout.
• No stdout or stderr is returned.
• It must be manually terminated.
• Running with elevated/unsandboxed permission behaves identically.

The same behavior occurs with:

• Get-Location
• reading a small text attachment with Get-Content
• git status --short
• rg
• cmd.exe /d /c ...

Additional isolation

The app's bundled Node REPL worker also times out before reading one small local file:

const fs = await import('node:fs/promises');
await fs.readFile('C:/.../pasted-text.txt', 'utf8');

Result: js execution timed out; kernel reset, rerun your request.

In contrast, non-child-process services work normally in the same task:

• Codex app workspace-dependency discovery responds immediately.
• GitHub connector calls respond immediately.
• Web requests respond immediately.

This strongly localizes the failure to the Windows app's local child-process / command-runner layer rather than the repository, network, or model.

Troubleshooting already attempted

• Restarted the Codex app.
• Restarted the task.
• Fully rebooted Windows.
• Retried after reboot.
• Retried with sandbox disabled/elevated permission.
• Tried PowerShell, cmd.exe, bundled Node, Git, and ripgrep paths.

The failure remains reproducible and blocks all local code inspection, editing, builds, tests, and Git operations.

Expected behavior

Trivial local commands should execute and return stdout promptly. A timeout should terminate the child process and return actionable stdout/stderr.

Impact

The coding agent is unusable for local development. It cannot read the attached implementation plan or safely inspect and modify the repository.

Possibly related

• #20874 reports dropped Windows command output and hangs, but that report describes intermittent behavior around completed/redirected commands. This report is an always-on regression affecting even Get-Location and the bundled Node worker.
• #19100 and #13917 describe Windows PowerShell-host startup failures, but those reports surfaced error 8009001d; this reproduction returns no error at all.