diff --git a/src/main.py b/src/main.py
index 18b292b..5cce3a2 100644
--- a/src/main.py
+++ b/src/main.py
@@ -29,6 +29,7 @@ def main():
         or len(app_settings.java_vms) == 0
         or len(app_settings.saxon_jars) == 0
         or len(app_settings.xsl_dirs) == 0
+        or len(app_settings.pdf_projects) == 0
     ):
         # Als Modal Dialog öffnen!
         dlg = AppSettingsDlg(window, app_settings)