Summary
The Codex VS Code extension never finishes loading because the bundled native executable (codex.exe) crashes immediately during startup.
The issue occurs before authentication, before any network requests are made, and before the extension finishes initialization.
After extensive debugging, I confirmed that the problem is not related to VS Code, the extension host, authentication, network connectivity, or my ChatGPT account. The bundled executable itself fails when launched directly from the command line.
Environment
Operating System
- Windows 11 Pro
- Version 24H2
- Build 26200.8655
Visual Studio Code
- Version: 1.128.0
Extension
- Extension:
openai.chatgpt - Version:
26.707.31428
Hardware
CPU
- AMD Ryzen 7 9800X3D
GPU
- NVIDIA GeForce RTX 5070
Motherboard
- ASUS TUF GAMING B650M-E WIFI
BIOS
- Version: 3841
- Release Date: 2026-02-24
Expected Behavior
Opening the Codex sidebar should initialize the extension and display the ChatGPT authentication screen.
Actual Behavior
The sidebar remains indefinitely on the loading screen (OpenAI logo).
The authentication screen never appears.
No requests are sent to the authentication endpoints.
Reproduction
- Install the latest version of Visual Studio Code.
- Install the latest OpenAI Codex extension.
- Open the Codex sidebar.
- Observe that it remains permanently on the loading screen.
Most Important Finding
Running the bundled executable directly reproduces the failure without involving VS Code.
Executable:
codex.exe
Command:
codex.exe --version
Output:
Fatal Error:
HW capability found: 0x178BFBFF 0xFED8320B,
but HW capability requested: 0x20000000 0x00.
The exact same error occurs with:
codex.exe
and
codex.exe --help
Therefore the native executable itself never starts successfully.
Troubleshooting Performed
I tested all of the following:
- Reinstalled Visual Studio Code.
- Deleted all VS Code settings.
- Deleted the extension cache.
- Installed only the OpenAI extension.
- Started VS Code using
--disable-extensions. - Started VS Code with a completely fresh user profile (
--user-data-dir). - Verified that Microsoft Edge WebView2 is installed.
- Verified that network connectivity is working.
- Verified that the OpenAI API is reachable.
- Compared against another Windows PC using the same account.
- Verified BIOS version and motherboard model.
None of these changed the behavior.
Network Verification
The machine has normal Internet connectivity.
Running:
curl https://api.openai.com/v1/models
returns the expected authentication error (“Missing bearer authentication”), confirming that the OpenAI API is reachable.
During extension startup, no authentication requests are initiated because the native executable terminates before initialization.
Comparison With Another Machine
I tested the exact same setup on another computer.
Same:
- ChatGPT account
- VS Code version
- Extension version
On the other machine, Codex initializes correctly and displays the login screen.
The problem only occurs on this machine.
Extension Behavior
Based on the investigation, the startup sequence appears to be:
VS Code
↓
Extension activates
↓
Extension launches codex.exe
↓
codex.exe immediately exits with a fatal hardware capability error
↓
Extension waits indefinitely
↓
Sidebar remains stuck on loading
Observations
The issue appears to occur before:
- Authentication
- API communication
- Extension UI initialization
- Normal extension logic
The failure happens entirely inside the bundled native executable.
Request
Could the engineering team investigate the hardware capability detection performed during startup?
The executable consistently terminates with:
Fatal Error:
HW capability found: 0x178BFBFF 0xFED8320B,
but HW capability requested: 0x20000000 0x00.
This happens on an AMD Ryzen 7 9800X3D running Windows 11 24H2.
Since the executable crashes outside VS Code as well, it appears to be a native runtime or CPU feature detection issue rather than a VS Code extension issue.