diff --git a/lib/user.php b/lib/user.php
index 356be4decf..549319b3a7 100644
--- a/lib/user.php
+++ b/lib/user.php
@@ -104,10 +104,16 @@ class OC_User {
 					break;
 			}
 		}
-
 		true;
 	}
 
+	/**
+	 * remove all used backends
+	 */
+	public static function clearBackends(){
+		self::$_usedBackends=array();
+	}
+
 	/**
 	 * @brief Create a new user
 	 * @param $uid The username of the user to create