diff --git a/Examples/options/export_detector_gdml.py b/Examples/options/export_detector_gdml.py
index 948a88294..603050e82 100644
--- a/Examples/options/export_detector_gdml.py
+++ b/Examples/options/export_detector_gdml.py
@@ -30,4 +30,8 @@
 geodumpservice.gdml = "DetFCCeeCLD.gdml"
 ApplicationMgr().ExtSvc += [geodumpservice]
 
+# avoid error and remove output file if it already exists
+if os.path.isfile(geodumpservice.gdml):
+      os.remove(geodumpservice.gdml)
+