diff --git a/monkeysign/ui.py b/monkeysign/ui.py
index 7804477246d76a548a2aa9dc8717f61061ed1129..6c7c674cffec6bc75524d184706a84dca2a3639e 100644
--- a/monkeysign/ui.py
+++ b/monkeysign/ui.py
@@ -402,7 +402,12 @@ expects an EmailFactory email, but will not mail if nomail is set"""
                 if self.options.dryrun: return True
                 command = [x % {'to': msg.mailto}
                            for x in shlex.split(self.options.mta)]
-                p = subprocess.Popen(command, stdin=subprocess.PIPE)  # nosec
+                try:
+                    p = subprocess.Popen(command, stdin=subprocess.PIPE)  # nosec
+                except OSError as e:
+                    self.warn(_('cannot find MTA %s, try --mta or --smtp: %s')
+                              % (command, e))
+                    return False
                 p.communicate(msg.as_string().encode('utf-8'))
                 self.warn(_('sent message to %(destination)s with %(command)s')
                           % {'destination': msg.mailto,