Regression in Codex App 26.813.12317 on Windows 10: pwsh commands fail:"Unknown Hard Error", while 26.730.61639 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?

Microsoft Windows NT 10.0.19045.0 x64

What issue are you seeing?

After updating Codex App from version 26.730.61639 to 26.813.12317 on Microsoft Windows NT 10.0.19045.0 x64, Codex App can no longer execute local PowerShell commands.

Prompt used:

Get-Date
Observed behavior:
A pwsh.exe window opens and displays:
Unknown Hard Error
Codex then reports:
Fatal error.
Your Windows doesn't fully support CET.
Please install all available Windows updates.
The command fails with exit code -2146233082.
This problem only occurs with Codex App 26.813.12317. After rolling back to Codex App 26.730.61639, the same Get-Date command works normally on the same computer.
Codex CLI also works normally on the same machine. No personally identifiable information is included.

### What steps can reproduce the bug?

### Environment

- Codex App version with the bug: 26.813.12317
- Codex App version without the bug: 26.730.61639
- Operating system: Microsoft Windows NT 10.0.19045.0 x64
- Shell: pwsh / PowerShell
- Codex CLI: Works normally on the same machine

### Steps to reproduce

1. Install or update Codex App to version 26.813.12317 on Windows 10.
2. Create a new task.
3. Ask Codex to execute this simple command:

```powershell
Get-Date
A pwsh.exe window appears with Unknown Hard Error.
The command fails with:
Fatal error.
Your Windows doesn't fully support CET.
Please install all available Windows updates.
Uninstall or roll back Codex App to version 26.730.61639.
Run the same Get-Date command again.
Comparison
Codex App 26.813.12317: command execution fails.
Codex App 26.730.61639: command execution works normally.
Codex CLI: command execution works normally on the same machine.
The issue started after updating from 26.730.61639 to 26.813.12317.
Session ID: Not available. The failure occurs before the local command can run.
Token limit usage: Not applicable.
Context window usage: Not applicable.

### What is the expected behavior?

Codex App should execute local PowerShell commands normally on Windows 10.

The command:

```powershell
Get-Date
should return the current date and time without opening an error window.
The same Windows installation and command work correctly with Codex App 26.730.61639 and Codex CLI.

**Additional information**

```markdown
This appears to be a version-specific regression in Codex App 26.813.12317.

The operating system has not changed. Only the Codex App version was changed:

- 26.730.61639: works
- 26.813.12317: fails

Changing the sandbox setting to Full Access did not resolve the problem.

Rolling back to Codex App 26.730.61639 immediately restored normal `pwsh` command execution.

Please investigate the bundled Windows command runner or runtime introduced in 26.813.12317 and consider provid

### Additional information

_No response_

Reproduce on Windows 10 using Codex App 26.813.12317 and the Get-Date PowerShell command, then compare with 26.730.61639 and Codex CLI. Investigate the bundled Windows command runner or runtime introduced in 26.813.12317; done means local PowerShell commands execute successfully without the Unknown Hard Error.