diff --git a/src/libnative/io/mod.rs b/src/libnative/io/mod.rs
index 3b0dbe2d0dc..4c5929ef223 100644
--- a/src/libnative/io/mod.rs
+++ b/src/libnative/io/mod.rs
@@ -77,7 +77,7 @@ fn unimpl() -> IoError {
     IoError {
         code: ERROR as uint,
         extra: 0,
-        detail: None,
+        detail: Some("not yet supported by the `native` runtime, maybe try `green`.".to_string()),
     }
 }