diff --git a/src/main/updater.js b/src/main/updater.js
index 2fec910..ccf46a9 100644
--- a/src/main/updater.js
+++ b/src/main/updater.js
@@ -7,7 +7,40 @@ const os = require('os');
 const path = require('path');
 const i18n = require('../i18n');
 
-const DEFAULT_REPO = 'https://git.mrblake.cc/MrBlake/MrTerm';
+// Startet ein Programm und liefert den Exit-Code ('ENOENT', falls es nicht existiert)
+function run(cmd, args) {
+  return new Promise((resolve) => {
+    const p = spawn(cmd, args, { stdio: 'ignore' });
+    p.on('error', (e) => resolve(e.code === 'ENOENT' ? 'ENOENT' : e.message));
+    p.on('exit', (c) => resolve(c));
+  });
+}
+
+// Fallback ohne Polkit-Agent: pacman -U per sudo in einem Terminalfenster; wartet, bis das Fenster geschlossen ist.
+// Der Erfolg wird über eine Marker-Datei erkannt, da nicht jedes Terminal den Exit-Code durchreicht.
+async function installInTerminal(file) {
+  const q = (s) => `'${String(s).replace(/'/g, `'\\''`)}'`;
+  const marker = file + '.ok';
+  try { fs.unlinkSync(marker); } catch {}
+  const script = `sudo /usr/bin/pacman -U --noconfirm ${q(file)} && touch ${q(marker)} || { echo; read -rp "[Enter]"; }`;
+  const terms = [
+    ['konsole', ['--nofork', '-e', 'bash', '-c', script]],
+    ['gnome-terminal', ['--wait', '--', 'bash', '-c', script]],
+    ['kitty', ['bash', '-c', script]],
+    ['alacritty', ['-e', 'bash', '-c', script]],
+    ['foot', ['bash', '-c', script]],
+    ['xfce4-terminal', ['--disable-server', '-x', 'bash', '-c', script]],
+    ['xterm', ['-e', 'bash', '-c', script]],
+  ];
+  for (const [cmd, args] of terms) {
+    const c = await run(cmd, args);
+    if (c === 'ENOENT') continue;
+    return fs.existsSync(marker) ? 0 : c || 1;
+  }
+  return 'ENOENT';
+}
+
+const DEFAULT_REPO ='https://git.mrblake.cc/MrBlake/MrTerm';
 
 function parseRepo(url) {
   const u = new URL((url || DEFAULT_REPO).replace(/\.git$/, '').replace(/\/+$/, ''));
@@ -134,11 +167,12 @@ class Updater {
       app.relaunch({ execPath: target });
       app.exit(0);
     } else if (kind === 'pacman' && /\.(pacman|pkg\.tar\.zst)$/.test(file)) {
-      await new Promise((resolve, reject) => {
-        const p = spawn('pkexec', ['pacman', '-U', '--noconfirm', file], { stdio: 'ignore' });
-        p.on('error', reject);
-        p.on('exit', (c) => (c === 0 ? resolve() : reject(new Error(i18n.t('pacman exited with code {code}', { code: c })))));
-      });
+      // 1. pkexec (grafische Passwortabfrage über den Polkit-Agent)
+      let code = await run('pkexec', ['/usr/bin/pacman', '-U', '--noconfirm', file]);
+      // 126/127 = Abfrage abgebrochen bzw. kein Polkit-Agent → Terminal mit sudo öffnen
+      if (code === 126 || code === 127 || code === 'ENOENT') code = await installInTerminal(file);
+      if (code === 'ENOENT') throw new Error(i18n.t('Automatic installation is not possible here. The file is located at: {file}', { file }));
+      if (code !== 0) throw new Error(i18n.t('pacman exited with code {code}', { code }));
       app.relaunch();
       app.exit(0);
     } else {