diff --git a/js/kiri-driver-fdm.js b/js/kiri-driver-fdm.js
index c0adcaa8..8c04d408 100644
--- a/js/kiri-driver-fdm.js
+++ b/js/kiri-driver-fdm.js
@@ -580,7 +580,7 @@ let gs_kiri_fdm = exports;
         // generate list of used extruders for purge blocks
         widgets.forEach(function(widget) {
             maxLayers = Math.max(maxLayers, widget.slices.length);
-            let extruder = settings.widget[widget.id].extruder;
+            let extruder = (settings.widget[widget.id] || {}).extruder || 0;
             if (!extruders[extruder]) {
                 extruders[extruder] = {};
                 extcount++;
diff --git a/js/kiri.js b/js/kiri.js
index bc1cf2b4..2f2adf26 100644
--- a/js/kiri.js
+++ b/js/kiri.js
@@ -1018,7 +1018,7 @@ self.kiri.copyright = exports.COPYRIGHT;
                 if (b) b.classList.remove('buton');
             }
             forSelectedWidgets(w => {
-                let ext = settings.widget[w.id].extruder || 0;
+                let ext = (settings.widget[w.id] || {}).extruder || 0;
                 let b = $(`sel-ext-${ext}`);
                 if (b) b.classList.add('buton');
             });