diff --git a/wp-admin/includes/class-wp-upgrader.php b/wp-admin/includes/class-wp-upgrader.php
index c70ef66bbb..f2db9ef97d 100644
--- a/wp-admin/includes/class-wp-upgrader.php
+++ b/wp-admin/includes/class-wp-upgrader.php
@@ -763,10 +763,7 @@ class Theme_Upgrader extends WP_Upgrader {
 			return $this->result;
 
 		// Force refresh of theme update information
-		delete_site_transient('update_themes');
-		search_theme_directories( true );
-		foreach ( wp_get_themes() as $theme )
-			$theme->cache_delete();
+		wp_clean_themes_cache();
 
 		return true;
 	}
@@ -812,10 +809,7 @@ class Theme_Upgrader extends WP_Upgrader {
 			return $this->result;
 
 		// Force refresh of theme update information
-		delete_site_transient('update_themes');
-		search_theme_directories( true );
-		foreach ( wp_get_themes() as $theme )
-			$theme->cache_delete();
+		wp_clean_themes_cache();
 
 		return true;
 	}
@@ -902,10 +896,7 @@ class Theme_Upgrader extends WP_Upgrader {
 		remove_filter('upgrader_clear_destination', array(&$this, 'delete_old_theme'), 10, 4);
 
 		// Force refresh of theme update information
-		delete_site_transient('update_themes');
-		search_theme_directories( true );
-		foreach ( wp_get_themes() as $theme )
-			$theme->cache_delete();
+		wp_clean_themes_cache();
 
 		return $results;
 	}
diff --git a/wp-includes/theme.php b/wp-includes/theme.php
index db7b0a2c72..b2b7ba48ae 100644
--- a/wp-includes/theme.php
+++ b/wp-includes/theme.php
@@ -106,6 +106,18 @@ function wp_get_theme( $stylesheet = null, $theme_root = null ) {
 	return new WP_Theme( $stylesheet, $theme_root );
 }
 
+/**
+ * Clears the cache held by get_theme_roots() and WP_Theme.
+ *
+ * @since 3.5.0
+ */
+function wp_clean_themes_cache() {
+	delete_site_transient('update_themes');
+	search_theme_directories( true );
+	foreach ( wp_get_themes( array( 'errors' => null ) ) as $theme )
+		$theme->cache_delete();
+}
+
 /**
  * Whether a child theme is in use.
  *