diff --git a/assignment-client/src/entities/EntityTreeHeadlessViewer.cpp b/assignment-client/src/entities/EntityTreeHeadlessViewer.cpp
index 81c42cda1e..3649cf1129 100644
--- a/assignment-client/src/entities/EntityTreeHeadlessViewer.cpp
+++ b/assignment-client/src/entities/EntityTreeHeadlessViewer.cpp
@@ -17,6 +17,9 @@ EntityTreeHeadlessViewer::EntityTreeHeadlessViewer()
 }
 
 EntityTreeHeadlessViewer::~EntityTreeHeadlessViewer() {
+    if (_simulation) {
+        _simulation->setEntityTree(nullptr);  // Break shared_ptr cycle.
+    }
 }
 
 void EntityTreeHeadlessViewer::init() {
diff --git a/libraries/entities/src/EntityTreeElement.h b/libraries/entities/src/EntityTreeElement.h
index f9f930a9fc..023e908e2c 100644
--- a/libraries/entities/src/EntityTreeElement.h
+++ b/libraries/entities/src/EntityTreeElement.h
@@ -161,7 +161,7 @@ public:
     virtual uint16_t size() const;
     bool hasEntities() const { return size() > 0; }
 
-    void setTree(EntityTreePointer tree) { _myTree.swap(std::weak_ptr<EntityTree>(tree)); }
+    void setTree(EntityTreePointer tree) { _myTree = std::weak_ptr<EntityTree>(tree); }
     EntityTreePointer getTree() const { return _myTree.lock(); }
 
     void addEntityItem(EntityItemPointer entity);