diff --git a/src/GUI/MessageBox.cxx b/src/GUI/MessageBox.cxx
index cb0000a25..1d8e5742f 100644
--- a/src/GUI/MessageBox.cxx
+++ b/src/GUI/MessageBox.cxx
@@ -4,6 +4,8 @@
 
 #include <simgear/simgear_config.h>
 
+#include <cstdlib>
+
 #include "MessageBox.hxx"
 
 #include <Main/fg_props.hxx>
@@ -146,16 +148,16 @@ MessageBoxResult modalMessageBox(const std::string& caption,
 #endif
 }
 
-MessageBoxResult fatalMessageBox(const std::string& caption,
-    const std::string& msg,
-    const std::string& moreText)
+[[noreturn]] void fatalMessageBox(const std::string& caption,
+                                  const std::string& msg,
+                                  const std::string& moreText)
 {
 #if defined(SG_WINDOWS)
-    return win32MessageBox(caption, msg, moreText);
+    win32MessageBox(caption, msg, moreText);
 #elif defined(SG_MAC)
-    return cocoaFatalMessage(msg, moreText);
+    cocoaFatalMessage(msg, moreText);
 #elif defined(HAVE_QT)
-    return QtMessageBox(caption, msg, moreText, true);
+    QtMessageBox(caption, msg, moreText, true);
 #else
     std::string s = "FATAL: "+ msg;
     if (!moreText.empty()) {
@@ -169,8 +171,9 @@ MessageBoxResult fatalMessageBox(const std::string& caption,
         dlg->setStringValue("text/label", s  );
         _gui->showDialog("popup");
     }
-    return MSG_BOX_OK;
 #endif
+
+    std::abort();
 }
 
 } // of namespace flightgear
diff --git a/src/GUI/MessageBox.hxx b/src/GUI/MessageBox.hxx
index 505b8ccfb..0811ceef0 100644
--- a/src/GUI/MessageBox.hxx
+++ b/src/GUI/MessageBox.hxx
@@ -6,7 +6,7 @@
 namespace flightgear
 {
 
-enum MessageBoxResult 
+enum MessageBoxResult
 {
     MSG_BOX_OK,
     MSG_BOX_YES,
@@ -17,10 +17,10 @@ MessageBoxResult modalMessageBox(const std::string& caption,
     const std::string& msg,
     const std::string& moreText = std::string());
 
-MessageBoxResult fatalMessageBox(const std::string& caption,
+[[noreturn]] void fatalMessageBox(const std::string& caption,
     const std::string& msg,
     const std::string& moreText = std::string());
-                
+
 } // of namespace flightgear
 
 #endif // of FG_GUI_MESSAGE_BOX_HXX
diff --git a/tests/testStubs.cxx b/tests/testStubs.cxx
index 4a08148fb..1f8a3e702 100644
--- a/tests/testStubs.cxx
+++ b/tests/testStubs.cxx
@@ -1,4 +1,5 @@
 #include <string>
+#include <cstdlib>
 
 #include <simgear/misc/sg_path.hxx>
 #include <simgear/structure/exception.hxx>
@@ -112,11 +113,11 @@ namespace flightgear
 	  return MSG_BOX_OK;
   }
 
-  MessageBoxResult fatalMessageBox(const std::string& caption,
+  [[noreturn]] void fatalMessageBox(const std::string& caption,
       const std::string& msg,
       const std::string& moreText)
   {
-	  return MSG_BOX_OK;
+	  std::abort();
   }
 }