diff --git a/BUILD_WINDOWS.md b/BUILD_WINDOWS.md
new file mode 100644
index 0000000..fb24444
--- /dev/null
+++ b/BUILD_WINDOWS.md
@@ -0,0 +1,45 @@
+# BUILD WINDOWS — hướng dẫn build installer (.exe) trên máy Windows
+
+## Yêu cầu trước khi build
+| Thành phần | Cài từ | Ghi chú |
+|---|---|---|
+| **Python 3.11+** | python.org | Tick **"Add to PATH"** |
+| **Node.js 20+** | nodejs.org | |
+| **Rust (MSVC toolchain)** | https://rustup.rs (hoặc script tự cài) | Cần cho Tauri |
+| **Visual Studio Build Tools** | visualstudio.microsoft.com | Workload **"Desktop development with C++"** (bắt buộc — MSVC linker cho Rust/Tauri) |
+| **WebView2 Runtime** | Windows 10/11 có sẵn; Windows 7/8 tải từ Microsoft | Tauri yêu cầu |
+
+> Nếu lỗi `cargo: program not found` → chưa cài Rust: chạy `rustup-init.exe -y` rồi **mở cmd MỚI** (PATH refresh).
+
+## Cách build — 1 lệnh
+```bat
+build_windows.bat
+```
+Script tự làm: cài Rust (nếu thiếu) → pip deps → Babel precompile → `pyinstaller engine.spec` (daw_engine.exe) → copy sidecar → `npx tauri build`.
+
+## Kết quả
+```
+src-tauri\target\release\bundle\nsis\SonicForgeDAW_1.0.0_x64-setup.exe   ← cài đặt (.exe)
+src-tauri\target\release\bundle\msi\SonicForgeDAW_1.0.0_x64_en-US.msi    ← MSI
+dist\daw_engine.exe                                                       ← engine đơn (debug)
+```
+
+## Thủ công (không dùng script)
+```bat
+pip install pyinstaller pywin32
+pip install -r requirements.txt
+pip install --no-deps pedalboard>=0.8.0
+node node_modules/@babel/cli/bin/babel.js app/static/js/app.jsx --config-file ./babel.config.json -o app/static/js/app.precompiled.js
+pyinstaller engine.spec --clean --noconfirm
+mkdir src-tauri\binaries
+copy dist\daw_engine.exe src-tauri\binaries\daw_engine-x86_64-pc-windows-msvc.exe
+npm install -D @tauri-apps/cli@^2
+npx tauri build
+```
+
+## Kiểm thử sau cài (spec — mục IV)
+1. Mở app → Task Manager: `daw_engine.exe` chạy nền; đóng app → tiến trình tắt hẳn (không orphan).
+2. Browser ngoài mở `http://localhost:8000/docs` → Swagger hiển thị.
+3. Plugin Manager → path `C:\Program Files\Common Files\VST3` → Scan → tìm thấy VST3 (Vital, Surge XT...).
+4. Export WAV → file chứa tiếng VST3 (qua pedalboard).
+5. Dữ liệu lưu tại `%APPDATA%\SonicForgeDAW\`.
diff --git a/build_windows.bat b/build_windows.bat
new file mode 100644
index 0000000..5378106
--- /dev/null
+++ b/build_windows.bat
@@ -0,0 +1,44 @@
+@echo off
+REM ── SonicForge DAW — Windows build script (Dual-Process: daw_engine.exe + Tauri shell) ──
+REM Chạy bằng "cmd" (Run as Administrator nếu cần cài Rust/system-wide)
+setlocal enabledelayedexpansion
+cd /d "%~dp0"
+
+echo [1/6] Kiem tra Python + Node...
+python --version || (echo THIEU Python 3.11+ — cai tu python.org (tick "Add to PATH") && pause && exit /b 1)
+node --version || (echo THIEU Node 20+ — cai tu nodejs.org && pause && exit /b 1)
+
+echo [2/6] Kiem tra / cai Rust toolchain (MSVC)...
+where cargo >nul 2>nul
+if errorlevel 1 (
+    echo Cai Rust qua rustup (MSVC toolchain — can Visual Studio Build Tools/C++ workload)...
+    powershell -Command "Invoke-WebRequest https://win.rustup.rs/x86_64 -OutFile rustup-init.exe"
+    rustup-init.exe -y --default-toolchain stable --profile minimal
+    del rustup-init.exe
+    call "%USERPROFILE%\.cargo\env" 2>nul || set "PATH=%USERPROFILE%\.cargo\bin;%PATH%"
+)
+cargo --version || (echo Rust cai that bai — cai Visual Studio Build Tools (C++ workload) roi thu lai && pause && exit /b 1)
+
+echo [3/6] Cai Python deps (PyInstaller + backend)...
+pip install pyinstaller pywin32
+pip install -r requirements.txt
+pip install --no-deps pedalboard>=0.8.0
+
+echo [4/6] Precompile JS (Babel)...
+npm install --no-audit --no-fund >nul 2>nul
+node node_modules/@babel/cli/bin/babel.js app/static/js/app.jsx --config-file ./babel.config.json -o app/static/js/app.precompiled.js || exit /b 1
+
+echo [5/6] Build daw_engine.exe (PyInstaller)...
+pyinstaller engine.spec --clean --noconfirm || exit /b 1
+if not exist "src-tauri\binaries" mkdir "src-tauri\binaries"
+copy /y dist\daw_engine.exe "src-tauri\binaries\daw_engine-x86_64-pc-windows-msvc.exe" >nul
+
+echo [6/6] Build Tauri installer (NSIS + MSI)...
+npm install -D @tauri-apps/cli@^2 >nul 2>nul
+call npx tauri build
+
+echo.
+echo HOAN TAT — Installer:
+echo   src-tauri\target\release\bundle\nsis\SonicForgeDAW_1.0.0_x64-setup.exe
+echo   src-tauri\target\release\bundle\msi\SonicForgeDAW_1.0.0_x64_en-US.msi
+pause
diff --git a/wiki.md b/wiki.md
index 3a09b0a..264c462 100644
--- a/wiki.md
+++ b/wiki.md
@@ -2972,3 +2972,9 @@
 - **FIX:** (1) requirements.txt — BỎ `pedalboard` (chú thích lý do); (2) CI — `pip install -r requirements.txt` + `pip install --no-deps pedalboard>=0.8.0` (chỉ pedalboard core — load_plugin VST3 KHÔNG cần supertonic).
 - **Các file ảnh hưởng:** requirements.txt, .github/workflows/windows-build.yml, wiki.md.
 - **Ghi chú/Test:** chạy lại workflow — hết conflict numpy; pedalboard (VST3 render) vẫn hoạt động qua --no-deps.
+
+### [2026-08-08 08:45] Task: FIX build Windows (3) — cargo not found (thiếu Rust)
+- **Lỗi:** `npx tauri build — failed to run 'cargo metadata' ... program not found` — máy build thiếu Rust toolchain.
+- **FIX:** (1) `build_windows.bat` — script 1 lệnh: kiểm tra Python/Node → TỰ CÀI Rust (rustup -y) nếu thiếu → pip deps (+ pedalboard --no-deps) → Babel → pyinstaller engine.spec → copy sidecar → npx tauri build; (2) `BUILD_WINDOWS.md` — yêu cầu (Python, Node, Rust MSVC, VS Build Tools C++, WebView2) + build thủ công + checklist kiểm thử theo spec IV.
+- **Các file ảnh hưởng:** build_windows.bat, BUILD_WINDOWS.md, wiki.md.
+- **Ghi chú/Test:** trên máy Windows: chạy `build_windows.bat` (cmd) → sinh setup.exe; CI (windows-latest — dtolnay/rust-toolchain) không bị lỗi này.