diff --git a/dol/filesys.py b/dol/filesys.py
index f2f7fe19..1080a8e6 100644
--- a/dol/filesys.py
+++ b/dol/filesys.py
@@ -275,7 +275,7 @@ def wrapped_method(self, k, *args, **kwargs):
         try:
             return func(self, k, *args, **kwargs)
         except Exception as e:
-            raise KeyError(e)
+            raise KeyError(str(e))
 
     return wrapped_method