diff --git a/src/swiftguistandard/swiftguistd.cpp b/src/swiftguistandard/swiftguistd.cpp
index 3798c425f..7287643ab 100644
--- a/src/swiftguistandard/swiftguistd.cpp
+++ b/src/swiftguistandard/swiftguistd.cpp
@@ -445,6 +445,7 @@ void SwiftGuiStd::verifyPrerequisites()
 
 void SwiftGuiStd::onValidatedModelSet(const CSimulatorInfo &simulator, const CAircraftModelList &valid, const CAircraftModelList &invalid, bool stopped, const CStatusMessageList &msgs)
 {
+    if (!sGui || sGui->isShuttingDown()) { return; }
     this->displayValidationDialog();
     m_validationDialog->validatedModelSet(simulator, valid, invalid, stopped, msgs);
 }