diff --git a/src/genworld.cpp b/src/genworld.cpp
index a876c31de6..dc881a9d85 100644
--- a/src/genworld.cpp
+++ b/src/genworld.cpp
@@ -338,7 +338,9 @@ void GenerateWorld(GenWorldMode mode, uint size_x, uint size_y, bool reset_setti
 	ShowGenerateWorldProgress();
 
 	/* Centre the view on the map */
-	ScrollMainWindowToTile(TileXY(MapSizeX() / 2, MapSizeY() / 2), true);
+	if (FindWindowById(WC_MAIN_WINDOW, 0) != nullptr) {
+		ScrollMainWindowToTile(TileXY(MapSizeX() / 2, MapSizeY() / 2), true);
+	}
 
 	_GenerateWorld();
 }
diff --git a/src/saveload/misc_sl.cpp b/src/saveload/misc_sl.cpp
index 345ca29677..81e44bc236 100644
--- a/src/saveload/misc_sl.cpp
+++ b/src/saveload/misc_sl.cpp
@@ -36,11 +36,13 @@ ZoomLevel _saved_scrollpos_zoom;
 
 void SaveViewportBeforeSaveGame()
 {
-	const Window *w = GetMainWindow();
+	const Window *w = FindWindowById(WC_MAIN_WINDOW, 0);
 
-	_saved_scrollpos_x = w->viewport->scrollpos_x;
-	_saved_scrollpos_y = w->viewport->scrollpos_y;
-	_saved_scrollpos_zoom = w->viewport->zoom;
+	if (w != nullptr) {
+		_saved_scrollpos_x = w->viewport->scrollpos_x;
+		_saved_scrollpos_y = w->viewport->scrollpos_y;
+		_saved_scrollpos_zoom = w->viewport->zoom;
+	}
 }
 
 void ResetViewportAfterLoadGame()
diff --git a/src/toolbar_gui.cpp b/src/toolbar_gui.cpp
index a6dd59296c..0e10548c2e 100644
--- a/src/toolbar_gui.cpp
+++ b/src/toolbar_gui.cpp
@@ -2196,7 +2196,8 @@ struct MainToolbarWindow : Window {
 	void OnInvalidateData(int data = 0, bool gui_scope = true) override
 	{
 		if (!gui_scope) return;
-		HandleZoomMessage(this, GetMainWindow()->viewport, WID_TN_ZOOM_IN, WID_TN_ZOOM_OUT);
+		Window *w = FindWindowById(WC_MAIN_WINDOW, 0);
+		if (w != nullptr) HandleZoomMessage(this, w->viewport, WID_TN_ZOOM_IN, WID_TN_ZOOM_OUT);
 	}
 
 	static HotkeyList hotkeys;
@@ -2577,7 +2578,8 @@ struct ScenarioEditorToolbarWindow : Window {
 	void OnInvalidateData(int data = 0, bool gui_scope = true) override
 	{
 		if (!gui_scope) return;
-		HandleZoomMessage(this, GetMainWindow()->viewport, WID_TE_ZOOM_IN, WID_TE_ZOOM_OUT);
+		Window *w = FindWindowById(WC_MAIN_WINDOW, 0);
+		if (w != nullptr) HandleZoomMessage(this, w->viewport, WID_TE_ZOOM_IN, WID_TE_ZOOM_OUT);
 	}
 
 	void OnQueryTextFinished(char *str) override
diff --git a/src/vehicle_gui.cpp b/src/vehicle_gui.cpp
index 8c2f6a346c..28dd228b60 100644
--- a/src/vehicle_gui.cpp
+++ b/src/vehicle_gui.cpp
@@ -4185,8 +4185,8 @@ bool VehicleClicked(const GUIVehicleGroup &vehgroup)
 
 void StopGlobalFollowVehicle(const Vehicle *v)
 {
-	Window *w = GetMainWindow();
-	if (w->viewport->follow_vehicle == v->index) {
+	Window *w = FindWindowById(WC_MAIN_WINDOW, 0);
+	if (w != nullptr && w->viewport->follow_vehicle == v->index) {
 		ScrollMainWindowTo(v->x_pos, v->y_pos, v->z_pos, true); // lock the main view on the vehicle's last position
 		w->viewport->follow_vehicle = INVALID_VEHICLE;
 	}