diff --git a/backend/utils/syncDatabase.js b/backend/utils/syncDatabase.js
index e9f5ff8..c5a3d5a 100644
--- a/backend/utils/syncDatabase.js
+++ b/backend/utils/syncDatabase.js
@@ -82,23 +82,35 @@ const syncDatabase = async () => {
                     console.log(`✅ ${deletedCount2} verwaiste stock Einträge entfernt`);
                 }
 
-                // Cleanup knowledge mit ungültigen character_id oder product_id
-                const result3 = await sequelize.query(`
-                    DELETE FROM falukant_data.knowledge
-                    WHERE character_id NOT IN (
-                        SELECT id FROM falukant_data.character
-                    ) OR product_id NOT IN (
-                        SELECT id FROM falukant_type.product
-                    );
-                `);
-                const deletedCount3 = result3[1] || 0;
-                if (deletedCount3 > 0) {
-                    console.log(`✅ ${deletedCount3} verwaiste knowledge Einträge entfernt`);
-                }
+            // Cleanup knowledge mit ungültigen character_id oder product_id
+            const result3 = await sequelize.query(`
+                DELETE FROM falukant_data.knowledge
+                WHERE character_id NOT IN (
+                    SELECT id FROM falukant_data.character
+                ) OR product_id NOT IN (
+                    SELECT id FROM falukant_type.product
+                );
+            `);
+            const deletedCount3 = result3[1] || 0;
+            if (deletedCount3 > 0) {
+                console.log(`✅ ${deletedCount3} verwaiste knowledge Einträge entfernt`);
+            }
 
-                if (deletedCount1 === 0 && deletedCount2 === 0 && deletedCount3 === 0) {
-                    console.log("✅ Keine verwaisten Einträge gefunden");
-                }
+            // Cleanup notification mit ungültigen user_id
+            const result4 = await sequelize.query(`
+                DELETE FROM falukant_log.notification
+                WHERE user_id NOT IN (
+                    SELECT id FROM falukant_data.falukant_user
+                );
+            `);
+            const deletedCount4 = result4[1] || 0;
+            if (deletedCount4 > 0) {
+                console.log(`✅ ${deletedCount4} verwaiste notification Einträge entfernt`);
+            }
+
+            if (deletedCount1 === 0 && deletedCount2 === 0 && deletedCount3 === 0 && deletedCount4 === 0) {
+                console.log("✅ Keine verwaisten Einträge gefunden");
+            }
             } catch (e) {
                 console.warn('⚠️  Konnte verwaiste Einträge nicht bereinigen:', e?.message || e);
             }
@@ -263,7 +275,19 @@ const syncDatabaseForDeployment = async () => {
                 console.log(`✅ ${deletedCount3} verwaiste knowledge Einträge entfernt`);
             }
 
-            if (deletedCount1 === 0 && deletedCount2 === 0 && deletedCount3 === 0) {
+            // Cleanup notification mit ungültigen user_id
+            const result4 = await sequelize.query(`
+                DELETE FROM falukant_log.notification
+                WHERE user_id NOT IN (
+                    SELECT id FROM falukant_data.falukant_user
+                );
+            `);
+            const deletedCount4 = result4[1] || 0;
+            if (deletedCount4 > 0) {
+                console.log(`✅ ${deletedCount4} verwaiste notification Einträge entfernt`);
+            }
+
+            if (deletedCount1 === 0 && deletedCount2 === 0 && deletedCount3 === 0 && deletedCount4 === 0) {
                 console.log("✅ Keine verwaisten Einträge gefunden");
             }
         } catch (e) {