diff --git a/src/mode/fdm/prepare.js b/src/mode/fdm/prepare.js
index d0b8c971..f2200066 100644
--- a/src/mode/fdm/prepare.js
+++ b/src/mode/fdm/prepare.js
@@ -408,7 +408,7 @@
                 layerout.appendAll(tmpout);
                 lastOut = slice;
                 lastExt = lastOut.ext
-                if (layerRetract) {
+                if (layerRetract && layerout.length) {
                     layerout.last().retract = true;
                 }
             }