diff --git a/src/GameLogic/Player.cs b/src/GameLogic/Player.cs
index c2899a6e2..d824fbaef 100644
--- a/src/GameLogic/Player.cs
+++ b/src/GameLogic/Player.cs
@@ -213,6 +213,7 @@ public Account? Account
                 this._accountLoggingScope?.Dispose();
                 this._accountLoggingScope = this.Logger.BeginScope("Account: {Name}", this._account!.LoginName);
                 this.IsVaultLocked = !string.IsNullOrWhiteSpace(this._account.VaultPassword);
+                this.LogInvalidVaultItems();
             }
         }
     }
@@ -1829,6 +1830,8 @@ private async ValueTask OnPlayerEnteredWorldAsync()
         this.AddMissingStatAttributes();
 
         this.Attributes = new ItemAwareAttributeSystem(this.Account!, this.SelectedCharacter!);
+        this.LogInvalidInventoryItems();
+
         this.Inventory = new InventoryStorage(this, this.GameContext);
         this.ShopStorage = new ShopStorage(this);
         this.TemporaryStorage = new Storage(InventoryConstants.TemporaryStorageSize, new TemporaryItemStorage());
@@ -1879,6 +1882,34 @@ await this.MagicEffectList.AddEffectAsync(new MagicEffect(
         }
     }
 
+    private void LogInvalidVaultItems()
+    {
+        var invalidItems = this.Account?.Vault?.Items.Where(i => i.Definition is null);
+        if (invalidItems is null)
+        {
+            return;
+        }
+
+        foreach (var item in invalidItems)
+        {
+            this.Logger.LogWarning("Account {name} has item without definition in vault, Slot: {slot}, ID: {id}", this.Account?.LoginName, item.ItemSlot, item.GetId());
+        }
+    }
+
+    private void LogInvalidInventoryItems()
+    {
+        var invalidItems = this.SelectedCharacter?.Inventory?.Items.Where(i => i.Definition is null);
+        if (invalidItems is null)
+        {
+            return;
+        }
+
+        foreach (var item in invalidItems)
+        {
+            this.Logger.LogWarning("Character {name} has item without definition in inventory, Slot: {slot}, ID: {id}", this.SelectedCharacter?.Name, item.ItemSlot, item.GetId());
+        }
+    }
+
     [System.Diagnostics.CodeAnalysis.SuppressMessage("Usage", "VSTHRD100:Avoid async void methods", Justification = "Catching all Exceptions.")]
     private async void OnTransformationSkinChanged(object? sender, EventArgs args)
     {
diff --git a/src/GameLogic/Storage.cs b/src/GameLogic/Storage.cs
index 2558dbb5b..64d6c0047 100644
--- a/src/GameLogic/Storage.cs
+++ b/src/GameLogic/Storage.cs
@@ -46,6 +46,7 @@ public Storage(int numberOfSlots, int boxOffset, int slotOffset, ItemStorage ite
         List<Item>? unfittingItems = null;
         this.ItemStorage.Items
             .Where(item => item.ItemSlot <= lastSlot && item.ItemSlot >= slotOffset)
+            .Where(item => item.Definition is not null)
             .ForEach(item =>
             {
                 if (!this.AddItemInternal((byte)(item.ItemSlot - slotOffset), item))
@@ -58,7 +59,7 @@ public Storage(int numberOfSlots, int boxOffset, int slotOffset, ItemStorage ite
         {
             return;
         }
-        
+
         // we first try to add them.
         for (var index = unfittingItems.Count - 1; index >= 0; index--)
         {