diff --git a/src/Moodle.WebCrawler/Views/MainWindow.cs b/src/Moodle.WebCrawler/Views/MainWindow.cs
index 705f343..8364242 100644
--- a/src/Moodle.WebCrawler/Views/MainWindow.cs
+++ b/src/Moodle.WebCrawler/Views/MainWindow.cs
@@ -188,6 +188,7 @@ private void MainWindow_FormClosing(object sender, FormClosingEventArgs e)
             {
                 e.Cancel = true;
                 ResetUserLanguageToDefault();
+                userPreferredLanguage = null;
 
                 Close();
             }