diff --git a/labelImg.py b/labelImg.py
index 6e3de46f..fcf66959 100755
--- a/labelImg.py
+++ b/labelImg.py
@@ -907,6 +907,7 @@ class MainWindow(QMainWindow, WindowMixin):
         if len(self.mImgList) <= 0:
             return
 
+        filename = None
         if self.filename is None:
             filename = self.mImgList[0]
         else: