diff --git a/components/favorites/FavoritesList.tsx b/components/favorites/FavoritesList.tsx
index 52e8c43..ff8a058 100644
--- a/components/favorites/FavoritesList.tsx
+++ b/components/favorites/FavoritesList.tsx
@@ -5,6 +5,7 @@
 import type { FavoriteItem } from '@/lib/types';
 import { FavoritesItem } from './FavoritesItem';
 import { FavoritesEmptyState } from './FavoritesEmptyState';
+import { keepRenderableFavorites } from '@/lib/utils/sync-records';
 
 interface FavoritesListProps {
     favorites: FavoriteItem[];
@@ -19,7 +20,7 @@ export function FavoritesList({ favorites, onRemove, isPremium = false }: Favori
 
     return (
         <div className="flex-1 overflow-y-auto -mx-2 px-2 space-y-2 scroll-smooth">
-            {favorites.map((item) => (
+            {keepRenderableFavorites(favorites).map((item) => (
                 <FavoritesItem
                     key={`${item.source}:${item.videoId}`}
                     item={item}
diff --git a/components/history/HistoryList.tsx b/components/history/HistoryList.tsx
index ecefbf4..9a4f829 100644
--- a/components/history/HistoryList.tsx
+++ b/components/history/HistoryList.tsx
@@ -1,6 +1,7 @@
 import { HistoryItem } from './HistoryItem';
 import { HistoryEmptyState } from './HistoryEmptyState';
 import type { VideoHistoryItem } from '@/lib/types';
+import { keepRenderableHistory } from '@/lib/utils/sync-records';
 
 interface HistoryListProps {
     history: VideoHistoryItem[];
@@ -18,7 +19,7 @@ export function HistoryList({ history, onRemove, isPremium = false }: HistoryLis
                 <HistoryEmptyState />
             ) : (
                 <div className="space-y-3">
-                    {history.map((item) => (
+                    {keepRenderableHistory(history).map((item) => (
                         <HistoryItem
                             key={item.showIdentifier}
                             item={item}
diff --git a/lib/hooks/useCloudSync.ts b/lib/hooks/useCloudSync.ts
index 0983079..bd4fa9a 100644
--- a/lib/hooks/useCloudSync.ts
+++ b/lib/hooks/useCloudSync.ts
@@ -1,6 +1,7 @@
 import { useState, useCallback } from 'react';
 import { useHistoryStore, usePremiumHistoryStore } from '@/lib/store/history-store';
 import { useFavoritesStore, usePremiumFavoritesStore } from '@/lib/store/favorites-store';
+import { keepRenderableFavorites, keepRenderableHistory } from '@/lib/utils/sync-records';
 import { getProfileId } from '@/lib/store/auth-store';
 
 export function useCloudSync(isPremium = false) {
@@ -19,11 +20,14 @@ export function useCloudSync(isPremium = false) {
       const result = await response.json();
 
       if (result.success && result.data) {
-        if (result.data.history?.length > 0) {
-          historyStore.getState().importHistory(result.data.history);
+        const history = keepRenderableHistory(result.data.history);
+        const favorites = keepRenderableFavorites(result.data.favorites);
+
+        if (history.length > 0) {
+          historyStore.getState().importHistory(history);
         }
-        if (result.data.favorites?.length > 0) {
-          favoritesStore.getState().importFavorites(result.data.favorites);
+        if (favorites.length > 0) {
+          favoritesStore.getState().importFavorites(favorites);
         }
       }
     } catch (error) {
diff --git a/lib/utils/sync-records.ts b/lib/utils/sync-records.ts
new file mode 100644
index 0000000..0d3dc7c
--- /dev/null
+++ b/lib/utils/sync-records.ts
@@ -0,0 +1,32 @@
+import type { FavoriteItem, VideoHistoryItem } from '@/lib/types';
+
+function hasIdentity(value: unknown): boolean {
+  if (!value || typeof value !== 'object') return false;
+  const record = value as { videoId?: unknown; source?: unknown; title?: unknown };
+  const videoId = record.videoId;
+  const hasVideoId = typeof videoId === 'string' ? videoId.length > 0 : typeof videoId === 'number';
+
+  return hasVideoId && typeof record.source === 'string' && typeof record.title === 'string';
+}
+
+/**
+ * Records restored from server-side sync are not guaranteed to be well formed —
+ * they may come from an older schema or a partial write. Rendering one without
+ * `videoId` throws while building the player URL, which takes down the whole
+ * page, so anything lacking a usable identity is dropped on the way in.
+ */
+export function isRenderableHistoryItem(value: unknown): value is VideoHistoryItem {
+  return hasIdentity(value);
+}
+
+export function isRenderableFavoriteItem(value: unknown): value is FavoriteItem {
+  return hasIdentity(value);
+}
+
+export function keepRenderableHistory(items: unknown): VideoHistoryItem[] {
+  return Array.isArray(items) ? items.filter(isRenderableHistoryItem) : [];
+}
+
+export function keepRenderableFavorites(items: unknown): FavoriteItem[] {
+  return Array.isArray(items) ? items.filter(isRenderableFavoriteItem) : [];
+}