diff --git a/mercurial/ui.py b/mercurial/ui.py
--- a/mercurial/ui.py
+++ b/mercurial/ui.py
@@ -409,7 +409,7 @@ class ui(object):
         if user is None and not self.interactive():
             try:
                 user = '%s@%s' % (util.getuser(), socket.getfqdn())
-                self.warn(_("No username found, using '%s' instead\n") % user)
+                self.warn(_("no username found, using '%s' instead\n") % user)
             except KeyError:
                 pass
         if not user:
diff --git a/tests/test-committer.t b/tests/test-committer.t
--- a/tests/test-committer.t
+++ b/tests/test-committer.t
@@ -53,7 +53,7 @@
   [255]
   $ rm .hg/hgrc
   $ hg commit -m commit-1 2>&1
-  No username found, using '[^']*' instead (re)
+  no username found, using '[^']*' instead (re)
 
   $ echo space > asdf
   $ hg commit -u ' ' -m commit-1