diff --git a/lib/base.php b/lib/base.php
index fb445124011d4d9699a733d76a88b4f8baca4fa3..5d52db68cb7730b28395ccee70f34a977d181e4c 100644
--- a/lib/base.php
+++ b/lib/base.php
@@ -554,7 +554,9 @@ class OC {
 		OC_Group::useBackend(new OC_Group_Database());
 
 		//setup extra user backends
-		OC_User::setupBackends();
+		if (!self::checkUpgrade(false)) {
+			OC_User::setupBackends();
+		}
 
 		self::registerCacheHooks();
 		self::registerFilesystemHooks();