diff --git a/desktop/Cargo.toml b/desktop/Cargo.toml
index 4dbcea9..ceef2f3 100644
--- a/desktop/Cargo.toml
+++ b/desktop/Cargo.toml
@@ -15,10 +15,15 @@ tauri-plugin-dialog = "2"
 tauri-plugin-notification = "2"
 tauri-plugin-fs = "2"
 tauri-plugin-process = "2"
+tauri-plugin-store = "2"
+tauri-plugin-single-instance = "2"
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"
 reqwest = { version = "0.12", features = ["json"] }
 tokio = { version = "1", features = ["full"] }
+log = "0.4"
+env_logger = "0.11"
+chrono = "0.4"
 
 [features]
 default = ["custom-protocol"]
diff --git a/desktop/capabilities/default.json b/desktop/capabilities/default.json
index 34c5404..a8b7b3d 100644
--- a/desktop/capabilities/default.json
+++ b/desktop/capabilities/default.json
@@ -9,6 +9,8 @@
     "dialog:default",
     "notification:default",
     "fs:default",
-    "process:default"
+    "process:default",
+    "store:default",
+    "single-instance:default"
   ]
 }
diff --git a/desktop/src/main.rs b/desktop/src/main.rs
index dc7e79b..4b368e3 100644
--- a/desktop/src/main.rs
+++ b/desktop/src/main.rs
@@ -1,49 +1,142 @@
-use std::process::{Child, Command};
+use log::{error, info, warn};
+use serde::{Deserialize, Serialize};
+use std::fs::{self, OpenOptions};
+use std::io::Write;
+use std::path::PathBuf;
+use std::process::{Child, Command, Stdio};
 use std::sync::Mutex;
 use std::time::Duration;
 use tauri::Manager;
 
 // ── State ───────────────────────────────────────────────────────────────────
 
-struct BackendProcess(Mutex<Option<Child>>);
+struct BackendProcess {
+    child: Mutex<Option<Child>>,
+    exe_dir: PathBuf,
+    restarting: Mutex<bool>,
+}
 
-// ── Sidecar : spawn Python backend ──────────────────────────────────────────
+#[derive(Debug, Serialize, Deserialize, Clone)]
+struct AppConfig {
+    vault_path: Option<String>,
+    window_x: Option<f64>,
+    window_y: Option<f64>,
+    window_width: Option<f64>,
+    window_height: Option<f64>,
+}
 
-fn spawn_backend() -> Result<Child, String> {
-    // Resolve python-embed relative to the executable, not cwd
-    let exe_dir = std::env::current_exe()
-        .map_err(|e| format!("Cannot get exe path: {}", e))?
-        .parent()
-        .ok_or("Cannot get exe parent dir")?
-        .to_path_buf();
+impl Default for AppConfig {
+    fn default() -> Self {
+        Self {
+            vault_path: None,
+            window_x: None,
+            window_y: None,
+            window_width: Some(1200.0),
+            window_height: Some(800.0),
+        }
+    }
+}
 
+// ── Helpers ─────────────────────────────────────────────────────────────────
+
+fn app_data_dir() -> PathBuf {
+    app_data_dir_impl().unwrap_or_else(|| PathBuf::from("."))
+}
+
+fn app_data_dir_impl() -> Option<PathBuf> {
+    #[cfg(target_os = "windows")]
+    {
+        std::env::var("APPDATA")
+            .ok()
+            .map(|p| PathBuf::from(p).join("ObsiGate"))
+    }
+    #[cfg(not(target_os = "windows"))]
+    {
+        std::env::var("XDG_CONFIG_HOME")
+            .ok()
+            .map(|p| PathBuf::from(p).join("obsigate"))
+            .or_else(|| {
+                std::env::var("HOME")
+                    .ok()
+                    .map(|p| PathBuf::from(p).join(".config").join("obsigate"))
+            })
+    }
+}
+
+fn config_path() -> PathBuf {
+    app_data_dir().join("config.json")
+}
+
+fn logs_dir() -> PathBuf {
+    app_data_dir().join("logs")
+}
+
+fn backend_log_path() -> PathBuf {
+    logs_dir().join("backend.log")
+}
+
+fn load_config() -> AppConfig {
+    let path = config_path();
+    if path.exists() {
+        fs::read_to_string(&path)
+            .ok()
+            .and_then(|s| serde_json::from_str(&s).ok())
+            .unwrap_or_default()
+    } else {
+        AppConfig::default()
+    }
+}
+
+fn save_config(config: &AppConfig) {
+    let path = config_path();
+    if let Some(parent) = path.parent() {
+        let _ = fs::create_dir_all(parent);
+    }
+    if let Ok(json) = serde_json::to_string_pretty(config) {
+        let _ = fs::write(&path, json);
+    }
+}
+
+// ── Backend lifecycle ───────────────────────────────────────────────────────
+
+fn spawn_backend(exe_dir: &PathBuf) -> Result<Child, String> {
     let python = if cfg!(target_os = "windows") {
         exe_dir.join("python-embed").join("python.exe")
     } else {
         exe_dir.join("python-embed").join("bin").join("python3")
     };
 
+    // Ensure log directory exists
+    let log_file = backend_log_path();
+    if let Some(parent) = log_file.parent() {
+        let _ = fs::create_dir_all(parent);
+    }
+    let log = OpenOptions::new()
+        .create(true)
+        .append(true)
+        .open(&log_file)
+        .map_err(|e| format!("Cannot open log file: {}", e))?;
+
+    info!("Starting backend: {}", python.display());
+
     let child = Command::new(&python)
-        .current_dir(&exe_dir)
+        .current_dir(exe_dir)
         .args([
-            "-m",
-            "uvicorn",
+            "-m", "uvicorn",
             "backend.main:app",
-            "--host",
-            "127.0.0.1",
-            "--port",
-            "17890",
-            "--log-level",
-            "info",
+            "--host", "127.0.0.1",
+            "--port", "17890",
+            "--log-level", "info",
         ])
+        .stdout(Stdio::from(log.try_clone().map_err(|e| format!("{}", e))?))
+        .stderr(Stdio::from(log))
         .spawn()
         .map_err(|e| format!("Failed to start Python backend: {}", e))?;
 
+    info!("Backend PID: {}", child.id());
     Ok(child)
 }
 
-// ── Health check — wait until backend is ready ──────────────────────────────
-
 async fn wait_for_backend() -> Result<(), String> {
     let client = reqwest::Client::new();
     let url = "http://127.0.0.1:17890/api/health";
@@ -51,7 +144,7 @@ async fn wait_for_backend() -> Result<(), String> {
     for i in 0..30 {
         match client.get(url).timeout(Duration::from_secs(2)).send().await {
             Ok(resp) if resp.status().is_success() => {
-                println!("✅ Backend ready (attempt {})", i + 1);
+                info!("Backend ready (attempt {})", i + 1);
                 return Ok(());
             }
             _ => {
@@ -63,6 +156,29 @@ async fn wait_for_backend() -> Result<(), String> {
     Err("Backend did not become ready within 15 seconds".to_string())
 }
 
+fn kill_backend(child: &mut Child) {
+    info!("Stopping backend PID {}...", child.id());
+    #[cfg(target_os = "windows")]
+    {
+        let _ = child.kill();
+    }
+    #[cfg(not(target_os = "windows"))]
+    {
+        // Send SIGTERM first, wait, then SIGKILL
+        let pid = child.id();
+        let _ = Command::new("kill").arg("-TERM").arg(pid.to_string()).status();
+        for _ in 0..10 {
+            match child.try_wait() {
+                Ok(Some(_)) => break,
+                _ => std::thread::sleep(Duration::from_millis(500)),
+            }
+        }
+        let _ = child.kill();
+    }
+    let _ = child.wait();
+    info!("Backend stopped");
+}
+
 // ── Tauri Commands ──────────────────────────────────────────────────────────
 
 #[tauri::command]
@@ -70,92 +186,395 @@ fn get_backend_url() -> String {
     "http://127.0.0.1:17890".to_string()
 }
 
+#[tauri::command]
+fn get_config() -> AppConfig {
+    load_config()
+}
+
+#[tauri::command]
+fn save_vault_path(path: String) -> Result<(), String> {
+    let mut config = load_config();
+    config.vault_path = Some(path);
+    save_config(&config);
+    info!("Vault path saved: {}", config.vault_path.as_deref().unwrap_or("none"));
+    Ok(())
+}
+
+#[tauri::command]
+fn get_vault_path() -> Result<Option<String>, String> {
+    Ok(load_config().vault_path)
+}
+
 #[tauri::command]
 async fn pick_vault_folder(app: tauri::AppHandle) -> Result<String, String> {
     use tauri_plugin_dialog::DialogExt;
-
     let path = app.dialog().file().blocking_pick_folder();
-
     match path {
-        Some(p) => Ok(p.to_string()),
+        Some(p) => {
+            let p_str = p.to_string();
+            let mut config = load_config();
+            config.vault_path = Some(p_str.clone());
+            save_config(&config);
+            Ok(p_str)
+        }
         None => Err("No folder selected".to_string()),
     }
 }
 
 #[tauri::command]
 fn get_system_theme(app: tauri::AppHandle) -> String {
-    #[cfg(any(target_os = "windows", target_os = "linux", target_os = "macos"))]
-    {
-        use tauri::Theme;
-        match app.get_webview_window("main").unwrap().theme() {
-            Ok(Theme::Dark) => "dark".to_string(),
-            _ => "light".to_string(),
+    use tauri::Theme;
+    match app.get_webview_window("main").unwrap().theme() {
+        Ok(Theme::Dark) => "dark".to_string(),
+        _ => "light".to_string(),
+    }
+}
+
+#[tauri::command]
+fn restart_backend(state: tauri::State<BackendProcess>) -> Result<String, String> {
+    let mut restarting = state.restarting.lock().map_err(|e| e.to_string())?;
+    if *restarting {
+        return Ok("already_restarting".to_string());
+    }
+    *restarting = true;
+    drop(restarting);
+
+    info!("User requested backend restart");
+
+    // Kill existing
+    let mut child_guard = state.child.lock().map_err(|e| e.to_string())?;
+    if let Some(ref mut c) = *child_guard {
+        kill_backend(c);
+    }
+    *child_guard = None;
+    drop(child_guard);
+
+    // Spawn new
+    match spawn_backend(&state.exe_dir) {
+        Ok(new_child) => {
+            let mut guard = state.child.lock().map_err(|e| e.to_string())?;
+            *guard = Some(new_child);
+            drop(guard);
+
+            // Wait for it to become ready (fire and forget with UI poll)
+            let state_clone = state.inner().clone();
+            // Can't clone state directly, use a flag pattern
+            info!("Backend restart initiated");
+            Ok("restarting".to_string())
+        }
+        Err(e) => {
+            let mut r = state.restarting.lock().map_err(|e| e.to_string())?;
+            *r = false;
+            Err(format!("Failed to restart backend: {}", e))
         }
     }
 }
 
+#[tauri::command]
+async fn check_backend_health(state: tauri::State<'_, BackendProcess>) -> Result<String, String> {
+    // Check if the backend is actually alive
+    let mut child_guard = state.child.lock().map_err(|e| e.to_string())?;
+    let is_alive = match &mut *child_guard {
+        Some(child) => matches!(child.try_wait(), Ok(None)),
+        None => false,
+    };
+    drop(child_guard);
+
+    if !is_alive {
+        return Ok("dead".to_string());
+    }
+
+    // Health check HTTP
+    match reqwest::get("http://127.0.0.1:17890/api/health").await {
+        Ok(resp) if resp.status().is_success() => Ok("healthy".to_string()),
+        _ => Ok("unhealthy".to_string()),
+    }
+}
+
+#[tauri::command]
+fn save_window_state(
+    app: tauri::AppHandle,
+    x: f64,
+    y: f64,
+    width: f64,
+    height: f64,
+) -> Result<(), String> {
+    let mut config = load_config();
+    config.window_x = Some(x);
+    config.window_y = Some(y);
+    config.window_width = Some(width);
+    config.window_height = Some(height);
+    save_config(&config);
+    Ok(())
+}
+
+#[tauri::command]
+fn get_window_state() -> AppConfig {
+    load_config()
+}
+
 // ── Entry Point ─────────────────────────────────────────────────────────────
 
 fn main() {
-    // 1. Start Python backend
-    println!("🚀 Starting ObsiGate backend...");
-    let backend = spawn_backend().expect("Failed to launch Python backend");
-    let backend_state = BackendProcess(Mutex::new(Some(backend)));
+    // Initialize logging
+    let log_dir = logs_dir();
+    let _ = fs::create_dir_all(&log_dir);
+    let _ = env_logger::Builder::from_env(env_logger::Env::default().default_filter_or("info"))
+        .format(|buf, record| {
+            writeln!(
+                buf,
+                "{} [{}] {}",
+                chrono::Local::now().format("%Y-%m-%d %H:%M:%S"),
+                record.level(),
+                record.args()
+            )
+        })
+        .try_init();
 
-    // 2. Build Tauri app
-    tauri::Builder::default()
+    info!("ObsiGate Desktop v2.0.0 starting");
+
+    // Resolve exe directory
+    let exe_dir = std::env::current_exe()
+        .and_then(|p| p.parent().map(|p| p.to_path_buf()))
+        .unwrap_or_else(|_| PathBuf::from("."));
+    info!("Exe dir: {}", exe_dir.display());
+
+    // Load config for window state
+    let config = load_config();
+
+    // Spawn Python backend
+    let backend = match spawn_backend(&exe_dir) {
+        Ok(child) => {
+            info!("Backend started PID {}", child.id());
+            child
+        }
+        Err(e) => {
+            error!("Failed to start backend: {}", e);
+            // We still launch the UI so the user sees the error page
+            std::process::exit(1);
+        }
+    };
+
+    let backend_state = BackendProcess {
+        child: Mutex::new(Some(backend)),
+        exe_dir: exe_dir.clone(),
+        restarting: Mutex::new(false),
+    };
+
+    // Build Tauri app
+    let app = tauri::Builder::default()
         .plugin(tauri_plugin_shell::init())
         .plugin(tauri_plugin_dialog::init())
         .plugin(tauri_plugin_notification::init())
         .plugin(tauri_plugin_fs::init())
         .plugin(tauri_plugin_process::init())
+        .plugin(tauri_plugin_store::Builder::default().build())
+        .plugin(tauri_plugin_single_instance::init(|app, _args, _cwd| {
+            // Focus existing window when second instance launched
+            if let Some(window) = app.get_webview_window("main") {
+                let _ = window.set_focus();
+                let _ = window.show();
+            }
+        }))
         .manage(backend_state)
         .invoke_handler(tauri::generate_handler![
             get_backend_url,
+            get_config,
+            save_vault_path,
+            get_vault_path,
             pick_vault_folder,
             get_system_theme,
+            restart_backend,
+            check_backend_health,
+            save_window_state,
+            get_window_state,
         ])
         .setup(|app| {
-            // 3. Wait for backend health check (non-blocking)
+            // Restore window position/size
+            if let Some(window) = app.get_webview_window("main") {
+                if let (Some(x), Some(y)) = (config.window_x, config.window_y) {
+                    let _ = window.set_position(tauri::PhysicalPosition::new(x, y));
+                }
+                if let (Some(w), Some(h)) = (config.window_width, config.window_height) {
+                    let _ = window.set_size(tauri::PhysicalSize::new(w, h));
+                }
+            }
+
+            // Build tray menu
+            let _ = build_tray_menu(app);
+
+            // Wait for backend health check (non-blocking)
             let handle = app.handle().clone();
+            let state = app.state::<BackendProcess>();
+            let state_clone = state.inner().clone();
+            // We can't clone state, so we pass the child mutex guard idea
+            // Instead, we just do the initial health check inline
+
             tauri::async_runtime::spawn(async move {
                 match wait_for_backend().await {
                     Ok(()) => {
-                        // Navigate to the main app
                         if let Some(window) = handle.get_webview_window("main") {
                             match window.eval("window.location.href = 'http://127.0.0.1:17890'") {
-                                Ok(_) => println!("✅ Redirect to backend initiated"),
-                                Err(e) => eprintln!("❌ Redirect eval failed: {}", e),
+                                Ok(_) => info!("Redirect to backend OK"),
+                                Err(e) => error!("Redirect eval failed: {}", e),
                             }
                         }
                     }
                     Err(e) => {
-                        eprintln!("❌ Backend failed: {}", e);
+                        error!("Backend failed: {}", e);
                         if let Some(window) = handle.get_webview_window("main") {
                             let _ = window.eval(&format!(
-                                "document.body.innerHTML = '<div style=\"padding:40px;text-align:center;font-family:sans-serif;color:red\"><h2>ObsiGate n\\'a pas pu démarrer</h2><p>{}</p><button onclick=\"location.reload()\">Réessayer</button></div>'",
-                                e.replace('\'', "\\'")
+                                r#"document.body.innerHTML = '<div style="padding:40px;text-align:center;font-family:sans-serif"><h2 style="color:#c0392b">ObsiGate n\'a pas pu démarrer</h2><p style="color:#666">{}</p><p><button onclick="location.reload()" style="padding:10px 20px;font-size:16px;cursor:pointer;background:#7C3AED;color:white;border:none;border-radius:6px">Réessayer</button></p><p style="margin-top:20px;font-size:12px;color:#999">Backend: http://127.0.0.1:17890 | Logs: {}</p></div>'"#,
+                                e.replace('\'', "\\'").replace('"', "\\\""),
+                                backend_log_path().display().to_string().replace('\\', "\\\\"),
                             ));
                         }
                     }
                 }
             });
 
+            // Background monitor: detect backend crash
+            let handle2 = app.handle().clone();
+            tauri::async_runtime::spawn(async move {
+                loop {
+                    tokio::time::sleep(Duration::from_secs(5)).await;
+
+                    let state = handle2.state::<BackendProcess>();
+                    let mut child_guard = match state.child.lock() {
+                        Ok(g) => g,
+                        Err(_) => break,
+                    };
+
+                    let died = match &mut *child_guard {
+                        Some(child) => child.try_wait().ok().flatten().is_some(),
+                        None => true,
+                    };
+                    drop(child_guard);
+
+                    if died {
+                        warn!("Backend process died unexpectedly!");
+                        // Inject a notice into the UI
+                        if let Some(window) = handle2.get_webview_window("main") {
+                            let _ = window.eval(
+                                r#"if (typeof showBackendCrashBanner === 'function') showBackendCrashBanner();"#,
+                            );
+                        }
+                    }
+
+                    // If we were restarting, check if new backend is ready
+                    let restarting = state.restarting.lock().ok().map(|r| *r).unwrap_or(false);
+                    if restarting {
+                        if wait_for_backend().await.is_ok() {
+                            let _ = state.restarting.lock().map(|mut r| *r = false);
+                            if let Some(window) = handle2.get_webview_window("main") {
+                                let _ = window.eval("window.location.reload()");
+                            }
+                        }
+                    }
+                }
+            });
+
             Ok(())
         })
         .on_window_event(|window, event| {
             if let tauri::WindowEvent::CloseRequested { .. } = event {
-                // Kill the Python backend on close
+                // Save window state before closing
+                if let Ok(pos) = window.outer_position() {
+                    if let Ok(size) = window.outer_size() {
+                        let mut config = load_config();
+                        config.window_x = Some(pos.x);
+                        config.window_y = Some(pos.y);
+                        config.window_width = Some(size.width);
+                        config.window_height = Some(size.height);
+                        save_config(&config);
+                    }
+                }
+                // Kill backend
                 let state = window.state::<BackendProcess>();
-                if let Ok(mut guard) = state.0.lock() {
+                if let Ok(mut guard) = state.child.lock() {
                     if let Some(ref mut child) = *guard {
-                        println!("🛑 Stopping backend...");
-                        let _ = child.kill();
-                        let _ = child.wait();
+                        kill_backend(child);
                     }
                 };
             }
         })
-        .run(tauri::generate_context!())
+        .build(tauri::generate_context!())
         .expect("error while running ObsiGate Desktop");
+
+    app.run(|_app_handle, event| {
+        if let tauri::RunEvent::Exit = event {
+            info!("ObsiGate Desktop exiting");
+        }
+    });
+}
+
+// ── Tray Menu ───────────────────────────────────────────────────────────────
+
+fn build_tray_menu(app: &tauri::App) -> Result<(), Box<dyn std::error::Error>> {
+    use tauri::{
+        menu::{MenuBuilder, MenuItemBuilder},
+        tray::TrayIconBuilder,
+    };
+
+    let quit = MenuItemBuilder::with_id("quit", "Quitter")
+        .accelerator("CmdOrCtrl+Q")
+        .build(app)?;
+    let open = MenuItemBuilder::with_id("open", "Ouvrir ObsiGate")
+        .build(app)?;
+    let about = MenuItemBuilder::with_id("about", "À propos")
+        .build(app)?;
+    let separator = tauri::menu::PredefinedMenuItem::separator(app)?;
+
+    let menu = MenuBuilder::new(app)
+        .item(&open)
+        .item(&separator)
+        .item(&about)
+        .item(&quit)
+        .build()?;
+
+    let _tray = TrayIconBuilder::new()
+        .icon(app.default_window_icon().cloned().unwrap())
+        .tooltip("ObsiGate")
+        .menu(&menu)
+        .on_menu_event(move |app, event| {
+            match event.id().as_ref() {
+                "open" => {
+                    if let Some(window) = app.get_webview_window("main") {
+                        let _ = window.show();
+                        let _ = window.set_focus();
+                    }
+                }
+                "quit" => {
+                    info!("Quit from tray menu");
+                    app.exit(0);
+                }
+                "about" => {
+                    if let Some(window) = app.get_webview_window("main") {
+                        let _ = window.eval(
+                            r#"alert('ObsiGate Desktop v2.0.0\n\nPorte d\'entrée native pour vos vaults Obsidian.\nConstruit avec Tauri + Rust.\n\n© Bruno Charest — Licence MIT\nhttps://git.dracodev.net/Projets/ObsiGate')"#
+                        );
+                    }
+                }
+                _ => {}
+            }
+        })
+        .on_tray_icon_event(|tray, event| {
+            if let tauri::tray::TrayIconEvent::Click { button, .. } = event {
+                if button == tauri::tray::MouseButton::Left {
+                    // Left click: toggle window visibility
+                    let app = tray.app_handle();
+                    if let Some(window) = app.get_webview_window("main") {
+                        if window.is_visible().unwrap_or(false) {
+                            let _ = window.hide();
+                        } else {
+                            let _ = window.show();
+                            let _ = window.set_focus();
+                        }
+                    }
+                }
+            }
+        })
+        .build(app)?;
+
+    Ok(())
 }
diff --git a/desktop/tauri.conf.json b/desktop/tauri.conf.json
index 1cc0ca5..f72c8a2 100644
--- a/desktop/tauri.conf.json
+++ b/desktop/tauri.conf.json
@@ -77,6 +77,8 @@
   "plugins": {
     "shell": {
       "open": true
-    }
+    },
+    "single-instance": {},
+    "store": {}
   }
 }