--- a/mail/test/mozmill/migration-from-tb2/prefs.js
+++ b/mail/test/mozmill/migration-from-tb2/prefs.js
@@ -9,16 +9,17 @@
  * For more information, see http://www.mozilla.org/unix/customizing.html#prefs
  */
 
 user_pref("app.update.lastUpdateTime.addon-background-update-timer", 1273257684);
 user_pref("app.update.lastUpdateTime.background-update-timer", 1273257684);
 user_pref("app.update.lastUpdateTime.blocklist-background-update-timer", 1273257684);
 user_pref("extensions.checkCompatibility.9.0a", false);
 user_pref("extensions.checkCompatibility.9.0", false);
+user_pref("extensions.testpilot.lastversion", "1.0");
 user_pref("intl.charsetmenu.mailview.cache", "windows-1252, ISO-8859-1, UTF-8");
 user_pref("ldap_2.prefs_migrated", true);
 user_pref("ldap_2.servers.default.filename", "default.mab");
 user_pref("ldap_2.servers.default.replication.lastChangeNumber", 0);
 user_pref("ldap_2.servers.default.uri", "moz-abldapdirectory://default.mab");
 user_pref("ldap_2.servers.history.replication.lastChangeNumber", 0);
 user_pref("ldap_2.servers.pab.replication.lastChangeNumber", 0);
 user_pref("mail.account.account1.server", "server1");

--- a/mail/test/mozmill/runtest.py
+++ b/mail/test/mozmill/runtest.py
@@ -135,16 +135,19 @@ class ThunderTestProfile(mozrunner.Thund
         # set the relative dirs properly
         'mail.root.none-rel' :  "[ProfD]Mail",
         'mail.root.pop3-rel' :  "[ProfD]Mail",
         # Do not allow check new mail to be set
         'mail.startup.enabledMailCheckOnce' :  True,
         # Disable compatibility checking
         'extensions.checkCompatibility.9.0a': False,
         'extensions.checkCompatibility.9.0': False,
+        # Disable test pilot new tab (this can be set to anything currently, just needs to be set).
+        'extensions.testpilot.lastversion': '1.0',
+
         # In case a developer is working on a laptop without a network
         # connection, don't detect offline mode; hence we'll still startup
         # online which is what mozmill currently requires. It'll also protect us
         # from any random network failures.
         'offline.autoDetect': False,
         # Don't load what's new or the remote start page - keep everything local
         # under our control.
         'mailnews.start_page_override.mstone' :  "ignore",