diff --git a/wp-includes/theme.php b/wp-includes/theme.php
index c4dc6435aa..3362c1d4ba 100644
--- a/wp-includes/theme.php
+++ b/wp-includes/theme.php
@@ -114,8 +114,9 @@ function get_themes() {
 
 	$themes = array();
 	$wp_broken_themes = array();
-	$theme_root = get_theme_root();
-	$theme_loc = str_replace(ABSPATH, '', $theme_root);
+	$theme_loc = $theme_root = get_theme_root();
+	if ( '/' != ABSPATH ) // don't want to replace all forward slashes, see Trac #4541
+		$theme_loc = str_replace(ABSPATH, '', $theme_root);
 
 	// Files in wp-content/themes directory and one subdir down
 	$themes_dir = @ opendir($theme_root);