diff --git a/sisyphus/loader.py b/sisyphus/loader.py
index 37ab948..08c856a 100644
--- a/sisyphus/loader.py
+++ b/sisyphus/loader.py
@@ -55,7 +55,7 @@ def load_config_file(self, config_name):
         except SyntaxError:
             import sys
 
-            if gs.USE_VERBOSE_TRACEBACK:
+            if gs.USE_VERBOSE_TRACEBACK and getattr(sys, "excepthook_org", None) is not None:
                 sys.excepthook = sys.excepthook_org
             raise