diff --git a/src/wp-admin/includes/class-theme-upgrader.php b/src/wp-admin/includes/class-theme-upgrader.php
index bb3e47d661..7e46b5f5a2 100644
--- a/src/wp-admin/includes/class-theme-upgrader.php
+++ b/src/wp-admin/includes/class-theme-upgrader.php
@@ -77,7 +77,8 @@ class Theme_Upgrader extends WP_Upgrader {
 		$this->strings['parent_theme_currently_installed'] = __('The parent theme, <strong>%1$s %2$s</strong>, is currently installed.');
 		/* translators: 1: theme name, 2: version */
 		$this->strings['parent_theme_install_success'] = __('Successfully installed the parent theme, <strong>%1$s %2$s</strong>.');
-		$this->strings['parent_theme_not_found'] = __('<strong>The parent theme could not be found.</strong> You will need to install the parent theme, <strong>%s</strong>, before you can use this child theme.');
+		/* translators: %s: theme name */
+		$this->strings['parent_theme_not_found'] = sprintf( __( '<strong>The parent theme could not be found.</strong> You will need to install the parent theme, %s, before you can use this child theme.' ), '<strong>%s</strong>' );
 	}
 
 	/**