diff --git a/compose/config.py b/compose/config.py
index aa2db2c71d..365fc3c27f 100644
--- a/compose/config.py
+++ b/compose/config.py
@@ -440,12 +440,12 @@ def resolve_volume_path(volume, working_dir, service_name):
 
         if not any(host_path.startswith(c) for c in PATH_START_CHARS):
             log.warn(
-                'Warning: the mapping "{0}" in the volumes config for '
-                'service "{1}" is ambiguous. In a future version of Docker, '
+                'Warning: the mapping "{0}:{1}" in the volumes config for '
+                'service "{2}" is ambiguous. In a future version of Docker, '
                 'it will designate a "named" volume '
                 '(see https://github.com/docker/docker/pull/14242). '
-                'To prevent unexpected behaviour, change it to "./{0}"'
-                .format(volume, service_name)
+                'To prevent unexpected behaviour, change it to "./{0}:{1}"'
+                .format(host_path, container_path, service_name)
             )
 
         return "%s:%s" % (expand_path(working_dir, host_path), container_path)