Ticket #16117: 16117.patch

wp-admin/network/themes.php

@@ -95 +95 @@
                         $main_theme = get_current_theme();
                         $files_to_delete = $theme_info = array();
                         foreach ( $themes as $key => $theme ) {
+                                if ( ! file_exists( WP_CONTENT_DIR . '/themes/' . $theme . '/style.css' ) ) {
+                                        unset( $themes[$key] );
+                                        continue;
+                                }
                                 $data = get_theme_data( WP_CONTENT_DIR . '/themes/' . $theme . '/style.css' );
                                 if ( $data['Name'] == $main_theme ) {
                                         unset( $themes[$key] );