diff --git a/backend/src/routes/admin.js b/backend/src/routes/admin.js
index b14d496..ee900fc 100644
--- a/backend/src/routes/admin.js
+++ b/backend/src/routes/admin.js
@@ -226,4 +226,44 @@ router.post('/webdav/test', authenticate, requireAdmin, async (req, res) => {
   }
 });
 
+// ── WebDAV Sync: alle lokalen Dateien auf NAS kopieren ────────────────────
+router.post('/webdav/sync', authenticate, requireAdmin, async (req, res) => {
+  const webdav = require('../tools/dateien/webdav');
+  const path   = require('path');
+  const fs     = require('fs');
+  const UPLOAD_DIR = process.env.UPLOAD_DIR || '/data/uploads';
+
+  const cfg = webdav.getConfig();
+  if (!cfg.enabled) return res.status(400).json({ error: 'WebDAV nicht aktiviert' });
+
+  // Alle Dateien aus DB holen mit Username
+  const files = db.prepare(`
+    SELECT f.*, u.username FROM files f
+    JOIN users u ON u.id = f.user_id
+    ORDER BY f.user_id, f.id
+  `).all();
+
+  const results = { ok: 0, failed: 0, errors: [] };
+
+  for (const file of files) {
+    const localPath = path.join(UPLOAD_DIR, file.filename);
+    if (!fs.existsSync(localPath)) {
+      results.failed++;
+      results.errors.push(`${file.originalname}: lokale Datei fehlt`);
+      continue;
+    }
+    try {
+      const buf = fs.readFileSync(localPath);
+      const davPath = webdav.userPath(cfg, file.username) + '/' + file.originalname;
+      await webdav.uploadFile(buf, davPath, file.mimetype || 'application/octet-stream');
+      results.ok++;
+    } catch(e) {
+      results.failed++;
+      results.errors.push(`${file.originalname}: ${e.message}`);
+    }
+  }
+
+  res.json({ total: files.length, ...results });
+});
+
 module.exports = router;
diff --git a/frontend/src/App.jsx b/frontend/src/App.jsx
index 724f43d..3107514 100644
--- a/frontend/src/App.jsx
+++ b/frontend/src/App.jsx
@@ -2702,6 +2702,8 @@ function WebDavSettings({ toast }) {
   const [cfg, setCfg] = useState({ url:'', user:'', password:'', basePath:'/dickendock', enabled:false });
   const [testing, setTesting] = useState(false);
   const [saving,  setSaving]  = useState(false);
+  const [syncing, setSyncing] = useState(false);
+  const [syncResult, setSyncResult] = useState(null);
   const [showPw,  setShowPw]  = useState(false);
 
   useEffect(() => {
@@ -2780,7 +2782,7 @@ function WebDavSettings({ toast }) {
         Synology WebDAV aktivieren: Systemsteuerung → Dateidienste → WebDAV
       </div>
 
-      <div style={{display:'flex',gap:8}}>
+      <div style={{display:'flex',gap:8,flexWrap:'wrap',marginBottom:12}}>
         <button onClick={test} disabled={testing || !cfg.url}
           style={{...S.btn('#60a5fa'), opacity:(testing||!cfg.url)?0.5:1}}>
           {testing ? '⏳ Teste...' : '🔌 Verbindung testen'}
@@ -2790,6 +2792,49 @@ function WebDavSettings({ toast }) {
           {saving ? '⏳...' : '💾 Speichern'}
         </button>
       </div>
+
+      {/* Sync Button */}
+      {cfg.enabled && (
+        <div style={{borderTop:'1px solid rgba(255,255,255,0.07)',paddingTop:14}}>
+          <div style={{color:'rgba(255,255,255,0.4)',fontFamily:'monospace',fontSize:10,marginBottom:8}}>
+            BESTEHENDE DATEIEN SYNCHRONISIEREN
+          </div>
+          <div style={{color:'rgba(255,255,255,0.3)',fontFamily:'monospace',fontSize:10,marginBottom:10,lineHeight:1.5}}>
+            Kopiert alle lokalen Dateien aus dem Docker-Container auf die Synology.
+            Bereits vorhandene Dateien werden überschrieben.
+          </div>
+          <button onClick={async()=>{
+            setSyncing(true); setSyncResult(null);
+            try {
+              const d = await api('/admin/webdav/sync', { body: {} });
+              setSyncResult(d);
+            } catch(e) { setSyncResult({ error: e.message }); }
+            finally { setSyncing(false); }
+          }} disabled={syncing}
+            style={{...S.btn('#f59e0b'), opacity:syncing?0.5:1, marginBottom:10}}>
+            {syncing ? '⏳ Synchronisiere...' : '📤 Alles auf Synology kopieren'}
+          </button>
+
+          {syncResult && !syncResult.error && (
+            <div style={{padding:'10px 12px',background:'rgba(74,222,128,0.08)',border:'1px solid rgba(74,222,128,0.3)',borderRadius:8,fontFamily:'monospace',fontSize:11}}>
+              <div style={{color:'#4ade80',marginBottom:4}}>
+                ✓ Sync abgeschlossen: {syncResult.ok}/{syncResult.total} erfolgreich
+              </div>
+              {syncResult.failed > 0 && (
+                <div style={{color:'#f87171'}}>
+                  ✗ {syncResult.failed} fehlgeschlagen
+                  {syncResult.errors?.slice(0,5).map((e,i) => (
+                    <div key={i} style={{color:'rgba(248,113,113,0.7)',fontSize:9,marginTop:2}}>· {e}</div>
+                  ))}
+                </div>
+              )}
+            </div>
+          )}
+          {syncResult?.error && (
+            <div style={{color:'#f87171',fontFamily:'monospace',fontSize:11}}>✗ {syncResult.error}</div>
+          )}
+        </div>
+      )}
     </div>
   );
 }