openai/codex · error

OpenMutexW failed: {err}

Error message

OpenMutexW failed: {err}

What it means

Error "OpenMutexW failed: {err}" thrown in openai/codex.

Source

Thrown at codex-rs/windows-sandbox-rs/src/bin/command_runner/win.rs:205

    };
    if msg.version != IPC_PROTOCOL_VERSION {
        anyhow::bail!("runner: unsupported protocol version {}", msg.version);
    }
    match msg.message {
        Message::SpawnRequest { payload } => Ok(*payload),
        other => anyhow::bail!("runner: expected spawn_request, got {other:?}"),
    }
}

fn read_acl_mutex_exists() -> Result<bool> {
    let name = to_wide(OsStr::new(READ_ACL_MUTEX_NAME));
    let handle = unsafe { OpenMutexW(MUTEX_ALL_ACCESS, 0, name.as_ptr()) };
    if handle == 0 {
        let err = unsafe { GetLastError() };
        if err == ERROR_FILE_NOT_FOUND {
            return Ok(false);
        }
        return Err(anyhow::anyhow!("OpenMutexW failed: {err}"));
    }
    unsafe {
        CloseHandle(handle);
    }
    Ok(true)
}

/// Pick an effective CWD, using a junction if the ACL helper is active.
fn effective_cwd(req_cwd: &Path, log_dir: Option<&Path>) -> PathBuf {
    let use_junction = match read_acl_mutex_exists() {
        Ok(exists) => exists,
        Err(err) => {
            log_note(
                &format!(
                    "junction: failed to probe ACL mutex state: {err}; defaulting to junction cwd"
                ),
                log_dir,
            );

View on GitHub (pinned to 339751715c)

When it happens

Trigger: Thrown at codex-rs/windows-sandbox-rs/src/bin/command_runner/win.rs:205 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of openai/codex@339751715c (2026-08-25). Data as JSON: /api/errors/6dc9aa270b1a63e9. Report an issue: GitHub.