Windows: app hangs ~30s on launch then crashes (0xc0000409) — bundled node.exe cannot resolve `\\?\`-prefixed server.js path (EISDIR 'C:')

[coolluo]

Environment

• OS: Windows 11 25H2 (x64)
• EchoType: EchoType_1.3.0_x64-setup.exe and EchoType_1.3.2_x64-setup.exe (both affected)
• WebView2 Runtime: 152.0.4191.66 (installed, not the problem)

Symptom

Double-click EchoType → process appears but shows no usable window ("Not Responding" if a window frame appears) → after ~30 seconds the process disappears silently. 100% reproducible on every launch, for both versions.

Windows Event Viewer (Application log) shows on every launch:

Faulting application name: echotype.exe, version: 1.3.0.0
Exception code: 0xc0000409          (BEX64, FAST_FAIL_FATAL_APP_EXIT, subcode 7)
Fault offset: 0x0000000000397f35

plus Application Hang (1002): The program echotype.exe stopped interacting with Windows.

Root cause

I captured the app's stderr by launching echotype.exe with redirected handles:

node:fs:2698
    const out = binding.lstat(pathModule.toNamespacedPath(base), false, undefined, true /* throwIfNoEntry */);
                        ^

Error: EISDIR: illegal operation on a directory, lstat 'C:'
    at Object.realpathSync (node:fs:2698:25)
    at toRealPath (node:internal/modules/helpers:58:13)
    at Module._findPath (node:internal/modules/cjs/loader:740:22)
    at resolveMainPath (node:internal/modules/run_main:34:23)
    at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:156:24)

thread 'main' panicked at tauri-2.10.3\src\app.rs:1299:11:
Failed to setup app: error encountered during setup hook: Server failed to start within 30 seconds

What happens step by step:

1. On Windows, the path built in src-tauri/src/sidecar.rs (get_server_path() / get_node_binary_path() via resource_dir()) ends up as a verbatim path with a \\?\ prefix (e.g. \\?\C:\Users\<user>\AppData\Local\EchoType\standalone\server.js).
2. This verbatim path is passed as the entry-script argument to the bundled binaries\node.exe. Node.js cannot resolve a \\?\-prefixed entry path and exits immediately with EISDIR: illegal operation on a directory, lstat 'C:'.
3. wait_for_server() then polls http://127.0.0.1:<port> for 30s while the main thread is blocked → the observed "hang / not responding".
4. The setup hook returns an error → Tauri panics → with panic = "abort" this surfaces as 0xc0000409 (BEX64) → process dies.

Minimal reproduction of the Node.js failure

Using the bundled node binary directly:

:: Fails — exactly what the app does:
node.exe "\\?\C:\Users\<user>\AppData\Local\EchoType\standalone\server.js"
→ Error: EISDIR: illegal operation on a directory, lstat 'C:'

:: Works — same file without the verbatim prefix:
node.exe "C:\Users\<user>\AppData\Local\EchoType\standalone\server.js"
→ ▲ Next.js 16.1.6 ... ✓ Ready in 2.4s

Suggested fix

In src-tauri/src/sidecar.rs, strip the verbatim prefix before passing paths to Command, e.g.:

let server_path = dunce::simplified(&server_path).to_path_buf();
let node_path = dunce::simplified(&node_path).to_path_buf();

or simply pass a relative entry since current_dir is already the standalone dir:

Command::new(&node_path)
    .arg("server.js")
    .current_dir(&working_dir)
    ...

Workaround I verified locally

I replaced binaries\node.exe with a tiny shim that strips the \\?\ prefix from its arguments and forwards them to the real node (renamed to node_real.exe). With this shim the app starts normally: window appears, embedded server responds HTTP 200. So the rest of the app is fine — it's purely this path-handling issue at startup.

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中文摘要

Windows 版启动必崩的原因：sidecar.rs 传给内置 node.exe 的 server.js 路径带 \\?\ 前缀，Node.js 解析不了这种 verbatim 路径而秒退（EISDIR 'C:'），Rust 侧等服务器 30 秒超时后 panic 崩溃。修复只需在传参前用 dunce::simplified() 去掉前缀，或直接传相对路径 server.js。所有 Windows 用户应该都会中招，建议尽快处理。

[Talljack]

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