[Windows] Codex extension fails with exit code 0xC0000135 (STATUS_DLL_NOT_FOUND) after Windows reinstall — missing VC++ Redistributable - A continous loading state

Resolved 💬 3 comments Opened Feb 17, 2026 by stackmasteraliza Closed Feb 17, 2026

💡 Likely answer: A maintainer (github-actions[bot], contributor) responded on this thread — see the highlighted reply below.

Environment

OS: Windows 11 Pro
VS Code: 1.109.4
Extension: openai.chatgpt v0.5.75 ("Codex – OpenAI's coding agent")

---

Problem

After a Windows reinstall, the Codex extension silently fails to start with no user-facing error.

The Codex sidebar shows a continuous loading indicator (infinite spinner) and never becomes usable. No error message, notification, or guidance is displayed.

---

Root Cause

From the extension log at:

%AppData%\Roaming\Code\logs\<session>\window1\exthost\openai.chatgpt\Codex.log

LOG OUTPUT:

[error] [CodexMcpConnection] Codex app-server process exited unexpectedly
(code=3221225781 (0xc0000135), signal=null)
[error] [CodexWebviewProvider] Fatal error: Codex process is not available

Exit code 0xC0000135 corresponds to Windows error:

STATUS_DLL_NOT_FOUND

The bundled codex.exe depends on the following runtime DLLs:

VCRUNTIME140.dll
MSVCP140.dll
VCRUNTIME140_1.dll

These are part of the Microsoft Visual C++ Redistributable 2015–2022, which is not included in a base Windows installation and gets removed after a system reinstall.

Because the dependency is missing, the Codex backend crashes immediately while the UI remains stuck showing an infinite spinner.

---

Fix (for users)

Installing the Visual C++ Redistributable resolves the issue.

PowerShell command:

$url = 'https://aka.ms/vs/17/release/vc_redist.x64.exe'
$out = "$env:TEMP\vc_redist.x64.exe"
Invoke-WebRequest -Uri $url -OutFile $out -UseBasicParsing
Start-Process -FilePath $out -ArgumentList '/install', '/quiet', '/norestart' -Wait
````

After installation:

Reload VS Code
Ctrl + Shift + P → Developer: Reload Window

View original on GitHub ↗

3 Comments

github-actions[bot] contributor · 6 months ago

Potential duplicates detected. Please review them and close your issue if it is a duplicate.

#11046

Powered by Codex Action

stackmasteraliza · 6 months ago

Update — Issue Resolved on My Side

I can confirm the root cause and fix.

The issue was caused by missing Microsoft Visual C++ runtime dependencies after a fresh Windows installation.

Because of this, the Codex backend process (codex.exe) was crashing immediately with exit code:

0xC0000135 (STATUS_DLL_NOT_FOUND)

This resulted in the extension showing a continuous loading spinner with no visible error.

---

Confirmed Fix

Installing the Microsoft Visual C++ Redistributable (2015–2022) fully resolves the issue.

Download:
https://aka.ms/vs/17/release/vc_redist.x64.exe

Or via PowerShell:

$url = 'https://aka.ms/vs/17/release/vc_redist.x64.exe'
$out = "$env:TEMP\vc_redist.x64.exe"
Invoke-WebRequest -Uri $url -OutFile $out -UseBasicParsing
Start-Process -FilePath $out -ArgumentList '/install', '/quiet', '/norestart' -Wait
````

After installation:
Reload VS Code → Ctrl + Shift + P → "Developer: Reload Window"

---

## Recommendation for Codex Team

To prevent silent failures for other users:

1. Detect exit code `0xC0000135` and show a clear message about missing VC++ runtime
   OR
2. Bundle required runtime DLLs with the Windows build

etraut-openai contributor · 6 months ago

Yes, this is covered in the troubleshooting section of our documentation.

Glad to hear you figured it out.