diff --git a/bottle.py b/bottle.py
index 7ac973c0..98324c17 100755
--- a/bottle.py
+++ b/bottle.py
@@ -3997,7 +3997,7 @@ def run(self):
         files = dict()
 
         for module in list(sys.modules.values()):
-            path = getattr(module, '__file__') or ''
+            path = getattr(module, '__file__', '') or ''
             if path[-4:] in ('.pyo', '.pyc'): path = path[:-1]
             if path and exists(path): files[path] = mtime(path)