diff --git a/lib/outputlib.php b/lib/outputlib.php
index 1a050032ef2..62db77ab987 100644
--- a/lib/outputlib.php
+++ b/lib/outputlib.php
@@ -543,7 +543,7 @@ class theme_config {
         if (file_exists($filename)) {
             ob_start();
             include_once($filename);
-            $metatags .= ob_get_contents();
+            $metatags = ob_get_contents();
             ob_end_clean();
         }
         return $metatags;
@@ -2590,4 +2590,4 @@ function output_css_for_css_edit($files, $toreplace) {
         }
         echo "/* @end */\n\n";
     }
-}
\ No newline at end of file
+}