Windows Computer Use fails with CreateProcessAsUserW error 5

Environment

• Codex app: 26.611.8604.0
• Computer Use plugin: 26.611.62324
• OS: Windows
• Permission mode: Full access

Problem

Computer Use and Chrome control cannot start. The failure occurs before connecting to Steam or any other target application.

Error:

CreateProcessAsUserW failed: 5

The failure occurs during list_apps() while initializing Computer Use.

Steps to reproduce

1. Ask Codex to control any Windows desktop application.
2. Codex initializes Computer Use.
3. The helper process immediately exits with error 5.

Troubleshooting attempted

• Restarted Codex and Windows applications
• Repaired Codex through Windows settings
• Updated Codex through Microsoft Store
• Started a new Codex thread
• Confirmed Codex and Steam run in the same Windows session
• Confirmed the issue also affects Chrome control

Expected behavior

Computer Use should start and list available Windows applications.

Actual behavior

The helper cannot be created and exits before any target application is accessed.