Codex crashes on Windows because of Avest CSP avsspc.dll — access violation 0xc0000005

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

ChatGPT Desktop / Codex Codex CLI 0.153.4 Avest CSP avsspc.dll version 6.1.3.1697

What subscription do you have?

Plus

What platform is your computer?

Windows 10/11

What issue are you seeing?

Environment:
Windows 10/11
ChatGPT Desktop / Codex
Codex CLI 0.153.4
Avest CSP avsspc.dll version 6.1.3.1697

Symptoms:
ChatGPT Desktop repeatedly showed “Something went wrong” when typing any character in the Codex input field.
Codex CLI also exited immediately after starting a request.

Windows Event Viewer:
Faulting application: codex.exe
Faulting module: avsspc.dll
Exception code: 0xc0000005
Fault offset: 0x0000000000013ca9

Path:
C:\Program Files\Common Files\Avest\Avest CSP\avsspc.dll

Debugging performed:

Reset/reinstalled ChatGPT Desktop
Recreated ~.codex\config.toml
Tested multiple Codex projects
Tested Codex CLI directly
Crash reproduced outside any specific project
Event Viewer identified avsspc.dll as the faulting module

Workaround:
Add codex.exe to the Avest CSP process exclusion list:

C:\Program Files\Common Files\Avest\Avest CSP\process

After restarting the application/system, Codex works normally.

This appears to be the same crash pattern as other applications affected by Avest CSP injection.

What steps can reproduce the bug?

What is the expected behavior?

No response

Additional information

I encountered a reproducible crash affecting Codex on Windows, both in the ChatGPT desktop application and when running the bundled codex.exe directly.

At first, the issue looked like a UI-specific problem in the Codex workspace inside the ChatGPT desktop app.

The ChatGPT desktop application itself could open normally. Regular ChatGPT chats worked fine, including typing and pasting text into the normal chat input.

However, as soon as I opened Codex and typed or pasted even a single character into the Codex input field, the application started repeatedly showing the error screen:

“Something went wrong.”

The error screen would flash repeatedly, alternating with the Codex UI, creating what looked like a crash/reload loop.

Initially, I suspected that the problem might be related to a specific Codex project. I deleted the original project, created a completely new project, and reproduced the exact same behavior. This confirmed that the crash was not related to a particular repository or workspace.

I then reset and reinstalled the ChatGPT desktop application, but the issue persisted.

I also recreated the Codex configuration file:

%USERPROFILE%.codex\config.toml

by renaming the existing file and allowing Codex to generate a new one. This did not resolve the crash either.

At this point, the behavior suggested that the issue might be deeper than the Codex desktop UI.

The ChatGPT desktop installation contained the following Codex executable:

C:\Users\User\AppData\Local\OpenAI\Codex\bin\8e5b6932251c2c1c\codex.exe

Running:

& "C:\Users\User\AppData\Local\OpenAI\Codex\bin\8e5b6932251c2c1c\codex.exe" --version

returned:

codex-cli 0.153.4

Running Codex directly from PowerShell showed that the CLI was also affected.

The interactive CLI would start, display its UI, and begin initializing MCP servers, but then exit unexpectedly back to PowerShell.

I also tested a non-interactive command:

& "C:\Users\User\AppData\Local\OpenAI\Codex\bin\8e5b6932251c2c1c\codex.exe" exec "Reply with one word: hello"
--skip-git-repo-check

The command started normally and displayed:

OpenAI Codex v0.153.4

workdir: C:\Windows\system32
model: gpt-6-astra
provider: openai
approval: never
sandbox: workspace-write

It also accepted the prompt:

user
Reply with one word: hello

but immediately exited back to PowerShell before returning any response.

This was an important observation because it showed that the issue was not limited to the Codex composer UI inside ChatGPT Desktop. The standalone codex.exe process itself was crashing as well.

Eventually, I found the relevant Windows Event Viewer crash entry.

The crash details were:

Faulting application name: codex.exe
Faulting application version: 0.0.0.0

Faulting module name: avsspc.dll
Faulting module version: 6.1.3.1697

Exception code: 0xc0000005
Fault offset: 0x0000000000013ca9

Faulting application path:
C:\Users\User\AppData\Local\OpenAI\Codex\bin\8e5b6932251c2c1c\codex.exe

Faulting module path:
C:\Program Files\Common Files\Avest\Avest CSP\avsspc.dll

The exception code 0xc0000005 indicates an access violation.

This strongly suggested that Codex itself was not the direct source of the crash. Instead, avsspc.dll, which belongs to Avest CSP, was being loaded into the codex.exe process and crashing inside that process.

The behavior was therefore:

Codex starts
→ Avest CSP injects/loads avsspc.dll
→ Codex performs some action such as initializing or processing input/request
→ avsspc.dll triggers an access violation
→ codex.exe terminates
→ ChatGPT Desktop detects the Codex failure and reloads/restarts part of the UI
→ repeated "Something went wrong" flashing

I found reports of the same Avest CSP module causing similar crashes in other applications, including the same:

avsspc.dll version 6.1.3.1697
exception code 0xc0000005
fault offset 0x13ca9

The workaround was to add the affected executable to the Avest CSP process exclusion list.

On my system, the relevant Avest CSP process exclusion file was located under:

C:\Program Files\Common Files\Avest\Avest CSP\process

After adding:

codex.exe

to the Avest CSP exclusion list and restarting the relevant applications/system components, Codex started working normally.

After applying this exclusion:

the Codex input field in ChatGPT Desktop stopped triggering the crash;
the repeated “Something went wrong” flashing disappeared;
Codex projects started working normally;
codex.exe no longer terminated immediately when processing a request.

So far, the issue appears resolved.

Environment
OS: Windows
ChatGPT Desktop: Windows desktop application
Codex CLI: 0.153.4
Codex desktop build observed in config: 26.901.51231
Avest CSP avsspc.dll: 6.1.3.1697
Troubleshooting performed before finding the root cause

• Reset ChatGPT Desktop
• Reinstalled ChatGPT Desktop
• Restarted Windows
• Tested multiple Codex projects
• Deleted the original Codex project and created a new one
• Confirmed normal ChatGPT chats were unaffected
• Confirmed the crash was triggered by typing or pasting any character in the Codex composer
• Recreated ~/.codex/config.toml
• Tested the bundled codex.exe directly
• Tested codex exec non-interactively
• Checked Windows Event Viewer
• Identified avsspc.dll as the faulting module
• Added codex.exe to the Avest CSP process exclusion list
• Confirmed the crash disappeared afterward
  Expected behavior

Codex should be able to run normally even when Avest CSP is installed on the system, or at minimum the application should detect/report the incompatible injected module instead of failing with a generic “Something went wrong” crash loop.

Actual behavior

avsspc.dll causes an access violation inside codex.exe, terminating the Codex process. In ChatGPT Desktop, this manifests as repeated flashing of the generic error screen.

Workaround

Add:

codex.exe

to the Avest CSP process exclusion list.

Additional note

The most misleading part of this issue was that it initially looked like a Codex UI or project-specific bug because the crash consistently appeared when interacting with the Codex input field.

Only after testing the bundled CLI separately did it become clear that the standalone codex.exe process was also terminating.

The Windows Event Viewer entry ultimately revealed that the actual faulting module was:

C:\Program Files\Common Files\Avest\Avest CSP\avsspc.dll

rather than Codex itself.

This may be useful for other Windows users who see repeated “Something went wrong” errors in Codex Desktop, especially if they have Avest CSP installed.

Start by reproducing the bundled codex.exe CLI commands on Windows with Avest CSP installed, then review the Windows Event Viewer details naming avsspc.dll, version 6.1.3.1697, and exception 0xc0000005. No source file or test is named; done means establishing a supported mitigation or a useful incompatibility diagnostic so Codex does not terminate silently, while preserving the documented process-exclusion workaround.