diff --git a/wp-admin/admin.php b/wp-admin/admin.php
index 88a4aa4..6591e9b 100644
--- a/wp-admin/admin.php
+++ b/wp-admin/admin.php
@@ -32,7 +32,7 @@ require_once(dirname(dirname(__FILE__)) . '/wp-load.php');
 
 nocache_headers();
 
-if ( get_option('db_upgraded') ) {
+if ( ! wp_doing_ajax() && get_option( 'db_upgraded' ) ) {
 	flush_rewrite_rules();
 	update_option( 'db_upgraded',  false );
 
@@ -42,7 +42,10 @@ if ( get_option('db_upgraded') ) {
 	 * @since 2.8.0
 	 */
 	do_action( 'after_db_upgrade' );
-} elseif ( get_option('db_version') != $wp_db_version && empty($_POST) ) {
+} elseif ( ! wp_doing_ajax() &&
+	get_option( 'db_version' ) != $wp_db_version &&
+	empty($_POST)
+) {
 	if ( !is_multisite() ) {
 		wp_redirect( admin_url( 'upgrade.php?_wp_http_referer=' . urlencode( wp_unslash( $_SERVER['REQUEST_URI'] ) ) ) );
 		exit;