diff --git a/panda/src/gui/guiButton.cxx b/panda/src/gui/guiButton.cxx
index 92ae611a8b..d6dd47bf26 100644
--- a/panda/src/gui/guiButton.cxx
+++ b/panda/src/gui/guiButton.cxx
@@ -111,6 +111,13 @@ static void click_button_up(CPT_Event e) {
 }
 
 void GuiButton::switch_state(GuiButton::States nstate) {
+  if (_mgr == (GuiManager*)0L) {
+    gui_cat.warning()
+      << "Tried to switch state of unmanaged button\n";
+    _state = nstate;
+    return;
+  }
+
   test_ref_count_integrity();
   States ostate = _state;
   // cleanup old state
diff --git a/panda/src/sgmanip/nodePath.cxx b/panda/src/sgmanip/nodePath.cxx
index c30f7de1fc..0f80d5dae8 100644
--- a/panda/src/sgmanip/nodePath.cxx
+++ b/panda/src/sgmanip/nodePath.cxx
@@ -2565,6 +2565,7 @@ r_get_net_transitions(const ArcComponent *comp,
 ////////////////////////////////////////////////////////////////////
 string NodePath::
 format_node_name(Node *node) const {
+  nassertr(node != (Node *)NULL, string());
   string name;
   if (node->is_of_type(NamedNode::get_class_type())) {
     name = DCAST(NamedNode, node)->get_name();