diff --git a/PorygonSharp/EvalValues/EvalValueCreator.cs b/PorygonSharp/EvalValues/EvalValueCreator.cs
index 8383e8f..732da53 100644
--- a/PorygonSharp/EvalValues/EvalValueCreator.cs
+++ b/PorygonSharp/EvalValues/EvalValueCreator.cs
@@ -43,8 +43,10 @@ namespace PorygonSharp.EvalValues
                 case TypeCode.Object:
                     if (typeof(IList).IsAssignableFrom(type))
                         return CreateListEvalValue((IList)o, type);
-                    if (!UserDataHandler.IsTypeRegistered(type))
-                        return null;
+                    if (!UserDataHandler.IsTypeRegistered(type) && !UserDataHandler.TryResolveType(type))
+                    {
+                        throw new Exception($"Type is not registered for use: {type.FullName}");
+                    }
                     var typeHash = UserDataHandler.GetTypeId(type);
                     var handle   = GCHandle.Alloc(o, GCHandleType.WeakTrackResurrection);
                     return new EvalValue(CreateUserDataEvalValue(typeHash, GCHandle.ToIntPtr(handle)));