diff --git a/wp-admin/includes/theme-install.php b/wp-admin/includes/theme-install.php
index 1f24e40a4..b1ad8a6ea 100644
--- a/wp-admin/includes/theme-install.php
+++ b/wp-admin/includes/theme-install.php
@@ -262,7 +262,7 @@ function install_theme_information() {
 	}
 
 	$themes = get_themes();
-	foreach ( $themes as $this_theme ) {
+	foreach ( (array) $themes as $this_theme ) {
 		if ( is_array($this_theme) && $this_theme['Stylesheet'] == $api->slug ) {
 			if ( $this_theme['Version'] == $api->version ) {
 				$type = 'latest_installed';