Codex App 26.813.12317: pwsh.exe "Unknown Hard Error" on Windows 10, while Codex CLI works

What version of the Codex App are you using (From “About Codex” dialog)?

26.813.12317

What subscription do you have?

pro

What platform is your computer?

windows10

What issue are you seeing?

下面这份可以直接提交到 openai/codex 的 Issues。只需将 Windows 版本号补充进去。

标题

Codex App 26.813.12317: pwsh.exe "Unknown Hard Error" on Windows 10, while Codex CLI works

正文

### Summary

After updating the Codex desktop app to version `26.813.12317`, local command execution stopped working on Windows 10.

Whenever Codex App tries to execute a local command, a `pwsh.exe` window appears with the message:

> Unknown Hard Error

The command then fails with the following output:

```text
Fatal error.
Your Windows doesn't fully support CET.
Please install all available Windows updates.

This appears to be a regression introduced by the latest Codex App update. Local command execution worked correctly before the update.

Environment

• Codex App version: 26.813.12317
• Operating system: Windows 10
• Windows version/build: Windows 10 22H2, OS Build 19045.2728
• Shell: PowerShell / pwsh
• Codex CLI: Works normally on the same machine
• Codex App UI and chat: Work normally

Steps to reproduce

1. Start Codex App on Windows 10.
2. Open or create a task.
3. Ask Codex to run any local command, for example:

Get-Date

4. A pwsh.exe window appears with Unknown Hard Error.
5. The command fails with the CET error shown above.

Actual behavior

Codex App cannot execute local commands. This prevents normal development tasks such as:

• Reading and searching project files through shell commands
• Running Git commands
• Running tests or builds
• Starting development servers
• Using npm, Maven, and other command-line tools

The process returned exit code -2146233082 during testing.

Expected behavior

Codex App should execute local commands normally on the same Windows 10 system, as it did before the update.

If the new runtime cannot run on this version of Windows, the app should provide a clear compatibility message instead of opening a pwsh.exe window with Unknown Hard Error.

Troubleshooting attempted

• Restarted Codex App
• Created/retried tasks after changing the configuration
• Changed the sandbox setting from Read Only to Full Access
• Confirmed that Codex CLI works correctly on the same machine

Changing the sandbox setting does not resolve the issue, suggesting that the crash occurs before or outside normal sandbox permission handling.

Additional context

The problem started immediately after updating Codex App to 26.813.12317.

Because Codex CLI works on the same machine, this appears specific to the desktop app's bundled command runner or workspace runtime and its CET compatibility on Windows 10.

Please consider providing a Windows 10-compatible runtime, a non-CET fallback, or a clearer compatibility check.

### What steps can reproduce the bug?

### Environment

- Codex App version: 26.813.12317
- OS: Windows 10, build Windows 10 22H2, build 19045.2728
- Codex CLI works normally on the same computer.
- The issue occurs in both Read Only and Full Access sandbox modes.

### Steps to reproduce

1. Start Codex App on Windows 10.
2. Create a new task.
3. Ask Codex to execute any local command, for example:

```powershell
Get-Date
A pwsh.exe window appears and displays Unknown Hard Error.
Local command execution fails with:
Fatal error.
Your Windows doesn't fully support CET.
Please install all available Windows updates.
The process returned exit code -2146233082.
This happens even with a new task and a simple command. It started immediately after updating Codex App to version 26.813.12317. The previous Codex App version worked on the same Windows installation.
Session ID: Not available
Token limit usage: Not applicable
Context window usage: Not applicable; the bug occurs on the first local command in a new task

### What is the expected behavior?

_No response_

### Additional information

_No response_

Start by reproducing the failure in Codex App on Windows 10 22H2 with a simple Get-Date command, then compare the app's bundled command runner with Codex CLI, which works on the same machine. Investigate the reported pwsh.exe Unknown Hard Error and CET message. Done means local commands run successfully or the app gives a clear compatibility message.