diff --git a/src/dobjtype.cpp b/src/dobjtype.cpp
index 0812ac9d5..668daafda 100644
--- a/src/dobjtype.cpp
+++ b/src/dobjtype.cpp
@@ -3084,6 +3084,7 @@ DObject *PClass::CreateNew()
 
 	if (ConstructNative == nullptr)
 	{
+		M_Free(mem);
 		I_Error("Attempt to instantiate abstract class %s.", TypeName.GetChars());
 	}
 	ConstructNative (mem);
diff --git a/src/dthinker.cpp b/src/dthinker.cpp
index a5d78a504..4b690efbc 100644
--- a/src/dthinker.cpp
+++ b/src/dthinker.cpp
@@ -709,7 +709,7 @@ DThinker *FThinkerIterator::Next (bool exact)
 
 class DThinkerIterator : public DObject, public FThinkerIterator
 {
-	DECLARE_CLASS(DThinkerIterator, DObject)
+	DECLARE_ABSTRACT_CLASS(DThinkerIterator, DObject)
 
 	DThinkerIterator()
 	{
@@ -722,7 +722,7 @@ public:
 	}
 };
 
-IMPLEMENT_CLASS(DThinkerIterator, false, false);
+IMPLEMENT_CLASS(DThinkerIterator, true, false);
 DEFINE_ACTION_FUNCTION(DThinkerIterator, Create)
 {
 	PARAM_PROLOGUE;
diff --git a/src/p_mobj.cpp b/src/p_mobj.cpp
index bfb3e3eec..5606a1102 100644
--- a/src/p_mobj.cpp
+++ b/src/p_mobj.cpp
@@ -7866,7 +7866,7 @@ DEFINE_ACTION_FUNCTION(AActor, GetBobOffset)
 
 class DActorIterator : public DObject, public NActorIterator
 {
-	DECLARE_CLASS(DActorIterator, DObject)
+	DECLARE_ABSTRACT_CLASS(DActorIterator, DObject)
 
 public:
 	DActorIterator(PClassActor *cls= nullptr, int tid = 0)
@@ -7875,7 +7875,7 @@ public:
 	}
 };
 
-IMPLEMENT_CLASS(DActorIterator, false, false);
+IMPLEMENT_CLASS(DActorIterator, true, false);
 DEFINE_ACTION_FUNCTION(DActorIterator, Create)
 {
 	PARAM_PROLOGUE;
diff --git a/src/scripting/vm/vmexec.h b/src/scripting/vm/vmexec.h
index ce3e3be22..b588d15d3 100644
--- a/src/scripting/vm/vmexec.h
+++ b/src/scripting/vm/vmexec.h
@@ -811,7 +811,19 @@ begin:
 	{
 		b = B;
 		PClass *cls = (PClass*)(pc->op == OP_NEW ? reg.a[b] : konsta[b].v);
-		if (cls->ObjectFlags & OF_Abstract) ThrowAbortException(X_OTHER, "Cannot instantiate abstract class %s", cls->TypeName.GetChars());
+		if (cls->ConstructNative == nullptr)
+		{
+			ThrowAbortException(X_OTHER, "Class %s requires native construction", cls->TypeName.GetChars());
+		}
+		if (cls->ObjectFlags & OF_Abstract)
+		{
+			ThrowAbortException(X_OTHER, "Cannot instantiate abstract class %s", cls->TypeName.GetChars());
+		}
+		// Creating actors here must be outright prohibited,
+		if (cls->IsDescendantOf(RUNTIME_CLASS(AActor)))
+		{
+			ThrowAbortException(X_OTHER, "Cannot create actors with 'new'");
+		}
 		// [ZZ] validate readonly and between scope construction
 		c = C;
 		if (c) FScopeBarrier::ValidateNew(cls, c - 1);