diff --git a/src/cuttlefish_conf.erl b/src/cuttlefish_conf.erl
index f22121df..79ef12dd 100644
--- a/src/cuttlefish_conf.erl
+++ b/src/cuttlefish_conf.erl
@@ -146,7 +146,7 @@ generate_comments(M) ->
     Default = case cuttlefish_mapping:default(M) of
                   undefined -> [];
                   Other ->
-                      [ "", ?FMT("Default: ~s", [cuttlefish_datatypes:to_string(Other, DefaultDT)]) ]
+                      [ "", ?FMT("Default: ~p", [cuttlefish_datatypes:to_string(Other, DefaultDT)]) ]
               end,
 
     Datatypes = ["", "Acceptable values:" |
diff --git a/src/cuttlefish_datatypes.erl b/src/cuttlefish_datatypes.erl
index f79779ea..2bf70860 100644
--- a/src/cuttlefish_datatypes.erl
+++ b/src/cuttlefish_datatypes.erl
@@ -160,6 +160,7 @@ to_string(Bytesize, bytesize) when is_list(Bytesize) -> Bytesize;
 to_string(Bytesize, bytesize) when is_integer(Bytesize) -> cuttlefish_bytesize:to_string(Bytesize);
 
 to_string(String, string) when is_list(String) -> String;
+to_string(Atom,   string) when is_atom(Atom) -> atom_to_list(Atom);
 
 to_string(File, file) when is_list(File) -> File;