diff --git a/Provision/Config/Drushrc/provision_drushrc_aegir.tpl.php b/Provision/Config/Drushrc/provision_drushrc_aegir.tpl.php
index 740f8c64..4cc8b1c0 100644
--- a/Provision/Config/Drushrc/provision_drushrc_aegir.tpl.php
+++ b/Provision/Config/Drushrc/provision_drushrc_aegir.tpl.php
@@ -23,6 +23,11 @@ print "# A list of paths that drush should include even when working outside\n";
 print "# the context of the hostmaster site.\n";
 print "\$options['include'] = ". var_export($drush_include, TRUE) . ";\n";
 
+print "# Prevent errors during hostmaster migration by avoiding double inclusion of autoloaders.\n";
+print "if (!empty(\$GLOBALS['AEGIR_DO_UPGRADE'])) {\n";
+print "  \$options['include'] = array();\n";
+print "}\n";
+
 print "# Local non-aegir-generated additions.\n";
 print "@include_once(dirname(__FILE__) . '/local.drushrc.php');\n";
 ?>
diff --git a/platform/deploy.provision.inc b/platform/deploy.provision.inc
index 86f056bb..34834eb5 100644
--- a/platform/deploy.provision.inc
+++ b/platform/deploy.provision.inc
@@ -92,6 +92,7 @@ function drush_provision_drupal_pre_provision_deploy($backup_file) {
     provision_save_site_data();
 
     // Load the newly created information, including re-loading the new db creds.
+    $GLOBALS['AEGIR_DO_UPGRADE'] = TRUE;
     drush_bootstrap(DRUSH_BOOTSTRAP_DRUPAL_SITE);
     _provision_drupal_create_settings_file();
     provision_drupal_push_site($override_slave_authority = TRUE);