--- a/client.py
+++ b/client.py
@@ -510,17 +510,18 @@ def fixup_comm_repo_options(options):
 
 
 def fixup_mozilla_repo_options(options):
     """Handle special case: initial checkout of Mozilla.
 
     See fixup_comm_repo_options().
     """
     if options.mozilla_repo is None:
-        if not os.path.exists(os.path.join(topsrcdir, 'mozilla')):
+        if (os.environ.get('MOZ_AUTOMATION') == '1'
+                or not os.path.exists(os.path.join(topsrcdir, 'mozilla'))):
             options.mozilla_repo = DEFAULTS['MOZILLA_REPO']
         else:
             # Fallback to using .hgrc as hgtool/share needs the repo
             import ConfigParser
             config = ConfigParser.ConfigParser()
             config_path = os.path.join(topsrcdir, 'mozilla', '.hg', 'hgrc')
             config.read([config_path])
             if not config.has_option('paths', 'default'):