diff --git a/src/SaveTool/SaveTool_MassViewer.cpp b/src/SaveTool/SaveTool_MassViewer.cpp
index 7ad9212..e284bba 100644
--- a/src/SaveTool/SaveTool_MassViewer.cpp
+++ b/src/SaveTool/SaveTool_MassViewer.cpp
@@ -19,6 +19,12 @@
 #include "SaveTool.h"
 
 void SaveTool::drawMassViewer() {
+    if(!_currentMass || _currentMass->state() != Mass::State::Valid) {
+        _currentMass = nullptr;
+        _uiState = UiState::MainManager;
+        return;
+    }
+
     ImGui::SetNextWindowPos({0.0f, ImGui::GetItemRectSize().y}, ImGuiCond_Always);
     ImGui::SetNextWindowSize({Float(windowSize().x()), Float(windowSize().y()) - ImGui::GetItemRectSize().y},
                              ImGuiCond_Always);