diff --git a/.mailmap b/.mailmap
index 3ba1110b09..e11a64ac9d 100644
--- a/.mailmap
+++ b/.mailmap
@@ -7,6 +7,7 @@ James Swaine        <jamesswaine@racket-lang.org> <james.swaine@gmail.com>
 Jens Axel Soegaard  <soegaard@racket-lang.org>    <jensaxel@soegaard.net>
 Matthew Flatt       <mflatt@racket-lang.org>      <mflatt@cs.utah.edu>
 Matthew Flatt       <mflatt@racket-lang.org>      <mflatt@debian.cs.utah.edu>
+Matthew Flatt       <mflatt@racket-lang.org>      <mflatt@localhost.(none)>
 Matthew Flatt       <mflatt@racket-lang.org>      <mflatt@mflatt-laptop.(none)>
 Matthew Flatt       <mflatt@racket-lang.org>      <mflatt@mflatt-VirtualBox.(none)>
 Kathy Gray          <kathyg@racket-lang.org>      <kathryn.gray@cl.cam.ac.uk>