diff --git a/picard/ui/mainwindow.py b/picard/ui/mainwindow.py
index 3b6e56583..67dff48a0 100644
--- a/picard/ui/mainwindow.py
+++ b/picard/ui/mainwindow.py
@@ -137,7 +137,7 @@ class MainWindow(QtGui.QMainWindow):
             msg.setText(_(u"Are you sure you want to quit Picard?"))
             txt = ungettext(
                 "There is %d unsaved file. Closing Picard will lose all unsaved changes.",
-                "There are %s unsaved files. Closing Picard will lose all unsaved changes.",
+                "There are %d unsaved files. Closing Picard will lose all unsaved changes.",
                 unsaved_files) % unsaved_files
             msg.setInformativeText(txt)
             cancel = msg.addButton(QMessageBox.Cancel)