diff --git a/src/kwordquiz.cpp b/src/kwordquiz.cpp
--- a/src/kwordquiz.cpp
+++ b/src/kwordquiz.cpp
@@ -979,7 +979,11 @@
       // the window and the application stay open.
       if(!w->close())
         break;
+      // Close the corresponding document to remove its lock file
+      static_cast<KWordQuiz *>(w)->document()->close();
     }
+    // Close the current document to get rid of its lock file either
+    m_doc->close();
   }
 }