diff --git a/apps/openmw/mwworld/esmstore.hpp b/apps/openmw/mwworld/esmstore.hpp
index ea6d3d006..c6c9c1ffe 100644
--- a/apps/openmw/mwworld/esmstore.hpp
+++ b/apps/openmw/mwworld/esmstore.hpp
@@ -166,16 +166,17 @@ namespace MWWorld
 
         template <class T>
         const T *insert(const T &x) {
+            std::ostringstream id;
+            id << "$dynamic" << mDynamicCount++;
+
             Store<T> &store = const_cast<Store<T> &>(get<T>());
-            if (store.search(x.mId) != 0) {
+            if (store.search(id.str()) != 0) {
                 std::ostringstream msg;
-                msg << "Try to override existing record '" << x.mId << "'";
+                msg << "Try to override existing record '" << id.str() << "'";
                 throw std::runtime_error(msg.str());
             }
             T record = x;
 
-            std::ostringstream id;
-            id << "$dynamic" << mDynamicCount++;
             record.mId = id.str();
 
             T *ptr = store.insert(record);
@@ -189,10 +190,13 @@ namespace MWWorld
 
         template <class T>
         const T *insertStatic(const T &x) {
+            std::ostringstream id;
+            id << "$dynamic" << mDynamicCount++;
+
             Store<T> &store = const_cast<Store<T> &>(get<T>());
-            if (store.search(x.mId) != 0) {
+            if (store.search(id.str()) != 0) {
                 std::ostringstream msg;
-                msg << "Try to override existing record '" << x.mId << "'";
+                msg << "Try to override existing record '" << id.str() << "'";
                 throw std::runtime_error(msg.str());
             }
             T record = x;
@@ -225,17 +229,18 @@ namespace MWWorld
 
     template <>
     inline const ESM::NPC *ESMStore::insert<ESM::NPC>(const ESM::NPC &npc) {
+        std::ostringstream id;
+        id << "$dynamic" << mDynamicCount++;
+
         if (Misc::StringUtils::ciEqual(npc.mId, "player")) {
             return mNpcs.insert(npc);
-        } else if (mNpcs.search(npc.mId) != 0) {
+        } else if (mNpcs.search(id.str()) != 0) {
             std::ostringstream msg;
-            msg << "Try to override existing record '" << npc.mId << "'";
+            msg << "Try to override existing record '" << id.str() << "'";
             throw std::runtime_error(msg.str());
         }
         ESM::NPC record = npc;
 
-        std::ostringstream id;
-        id << "$dynamic" << mDynamicCount++;
         record.mId = id.str();
 
         ESM::NPC *ptr = mNpcs.insert(record);