Index: src/wp-includes/capabilities.php
===================================================================
--- src/wp-includes/capabilities.php	(revision 38699)
+++ src/wp-includes/capabilities.php	(working copy)
@@ -470,7 +470,7 @@

 	$current_user = wp_get_current_user();

-	if ( empty( $current_user ) ) {
+	if ( ! $current_user->ID ) {
 		if ( $switched ) {
 			restore_current_blog();
 		}