diff --git a/app/main/index.ts b/app/main/index.ts
index a010a9a..fdedcd9 100644
--- a/app/main/index.ts
+++ b/app/main/index.ts
@@ -69,9 +69,37 @@ function createWindow(): void {
     },
   });
 
+  mainWindow.once('ready-to-show', () => {
+    mainWindow?.show();
+    mainWindow?.focus();
+  });
+  mainWindow.show();
+
   const devUrl = process.env.VITE_DEV_SERVER_URL;
   if (devUrl) {
-    void mainWindow.loadURL(devUrl);
+    mainWindow.webContents.openDevTools({ mode: 'detach' });
+    mainWindow.webContents.on('did-fail-load', (_e, code, desc, url) => {
+      console.error('did-fail-load', code, desc, url);
+    });
+    mainWindow.webContents.on('console-message', (_e, level, message) => {
+      console.log(`[renderer:${level}]`, message);
+    });
+    const load = async (attempt = 0) => {
+      try {
+        await mainWindow!.loadURL(devUrl);
+        console.log('Loaded', devUrl);
+      } catch (err) {
+        console.error('loadURL attempt', attempt, err);
+        if (attempt < 20) {
+          setTimeout(() => void load(attempt + 1), 300);
+          return;
+        }
+        await mainWindow!.loadURL(
+          `data:text/html,<h1 style="color:#fff;font-family:sans-serif;padding:24px">Dev server not reachable: ${devUrl}</h1>`,
+        );
+      }
+    };
+    void load();
   } else {
     void mainWindow.loadFile(path.join(__dirname, '../renderer/index.html'));
   }
diff --git a/app/renderer/App.tsx b/app/renderer/App.tsx
index c2b16f9..f4d22db 100644
--- a/app/renderer/App.tsx
+++ b/app/renderer/App.tsx
@@ -155,12 +155,22 @@ export function App() {
     void (async () => {
       if (!window.ttrpgBuilder) {
         setBooting(false);
+        setStatus(
+          locale === 'ru'
+            ? 'Нет связи с Electron preload (перезапустите npm run dev)'
+            : 'Electron preload missing (restart npm run dev)',
+        );
         return;
       }
-      await window.ttrpgBuilder.seedPresets();
-      await refresh();
-      setBooting(false);
-      setStatus(locale === 'ru' ? 'Пресеты готовы' : 'Presets ready');
+      try {
+        await window.ttrpgBuilder.seedPresets();
+        await refresh();
+        setStatus(locale === 'ru' ? 'Пресеты готовы' : 'Presets ready');
+      } catch (e) {
+        setStatus(String(e));
+      } finally {
+        setBooting(false);
+      }
     })();
   }, [refresh, locale]);
 
diff --git a/app/renderer/index.html b/app/renderer/index.html
index 0cdd555..e63f308 100644
--- a/app/renderer/index.html
+++ b/app/renderer/index.html
@@ -4,9 +4,13 @@
     <meta charset="UTF-8" />
     <meta name="viewport" content="width=device-width, initial-scale=1.0" />
     <title>TTRPG Character Builder</title>
+    <style>
+      html, body { margin: 0; height: 100%; background: #09090b; color: #eee; font-family: Segoe UI, sans-serif; }
+      #boot-fallback { padding: 24px; }
+    </style>
   </head>
   <body>
-    <div id="root"></div>
+    <div id="root"><div id="boot-fallback">Loading TTRPG Character Builder…</div></div>
     <script type="module" src="./main.tsx"></script>
   </body>
 </html>
diff --git a/app/renderer/main.tsx b/app/renderer/main.tsx
index 5d922b8..de0f83e 100644
--- a/app/renderer/main.tsx
+++ b/app/renderer/main.tsx
@@ -2,4 +2,21 @@ import { createRoot } from 'react-dom/client';
 import { App } from './App.tsx';
 import './styles.css';
 
-createRoot(document.getElementById('root')!).render(<App />);
+const rootEl = document.getElementById('root');
+if (!rootEl) {
+  document.body.innerHTML = '<pre style="color:#f66;padding:24px">#root missing</pre>';
+} else {
+  try {
+    createRoot(rootEl).render(<App />);
+  } catch (err) {
+    rootEl.innerHTML = `<pre style="color:#f66;padding:24px;white-space:pre-wrap">${String(err)}</pre>`;
+    console.error(err);
+  }
+}
+
+window.addEventListener('error', (e) => {
+  console.error('window.error', e.error || e.message);
+});
+window.addEventListener('unhandledrejection', (e) => {
+  console.error('unhandledrejection', e.reason);
+});
diff --git a/scripts/dev.mjs b/scripts/dev.mjs
index da42f49..5cc58cd 100644
--- a/scripts/dev.mjs
+++ b/scripts/dev.mjs
@@ -3,9 +3,11 @@ import { spawn } from 'node:child_process';
 import path from 'node:path';
 import { fileURLToPath } from 'node:url';
 import fs from 'node:fs';
+import http from 'node:http';
 
 const __dirname = path.dirname(fileURLToPath(import.meta.url));
 const root = path.resolve(__dirname, '..');
+const DEV_URL = 'http://127.0.0.1:5174/';
 
 async function buildMain() {
   await build({
@@ -35,24 +37,54 @@ function electronPath() {
   return path.join(root, 'node_modules', 'electron', 'cli.js');
 }
 
+function waitForUrl(url, timeoutMs = 60000) {
+  const start = Date.now();
+  return new Promise((resolve, reject) => {
+    const tick = () => {
+      const req = http.get(url, (res) => {
+        res.resume();
+        resolve(true);
+      });
+      req.on('error', () => {
+        if (Date.now() - start > timeoutMs) {
+          reject(new Error(`Timed out waiting for ${url}`));
+          return;
+        }
+        setTimeout(tick, 250);
+      });
+    };
+    tick();
+  });
+}
+
 await buildMain();
 
 const vite = spawn(
   process.platform === 'win32' ? 'npx.cmd' : 'npx',
-  ['vite', '--config', 'vite.config.ts'],
+  ['vite', '--config', 'vite.config.ts', '--host', '127.0.0.1', '--port', '5174'],
   { cwd: root, stdio: 'inherit', shell: true },
 );
 
-await new Promise((r) => setTimeout(r, 2000));
+console.log('Waiting for Vite…');
+await waitForUrl(DEV_URL);
+console.log('Vite is ready, launching Electron…');
 
 const elec = spawn(electronPath(), ['.'], {
   cwd: root,
   stdio: 'inherit',
   shell: true,
-  env: { ...process.env, VITE_DEV_SERVER_URL: 'http://localhost:5174' },
+  env: { ...process.env, VITE_DEV_SERVER_URL: DEV_URL },
 });
 
 elec.on('exit', (code) => {
   vite.kill();
   process.exit(code ?? 0);
 });
+
+vite.on('exit', (code) => {
+  if (code && code !== 0) {
+    console.error('Vite exited with code', code);
+    elec.kill();
+    process.exit(code);
+  }
+});
diff --git a/vite.config.ts b/vite.config.ts
index c6aa301..94c6cb5 100644
--- a/vite.config.ts
+++ b/vite.config.ts
@@ -11,6 +11,7 @@ export default defineConfig({
     emptyOutDir: true,
   },
   server: {
+    host: '127.0.0.1',
     port: 5174,
     strictPort: true,
   },