diff --git a/api/src/Mail/Html.php b/api/src/Mail/Html.php
index 470e871ae6..b8b55e08cf 100644
--- a/api/src/Mail/Html.php
+++ b/api/src/Mail/Html.php
@@ -564,7 +564,11 @@ class Html
 		{
 			// avoid infinit loop in case the endof pre can't be found, just give the
 			// end position to return the rest of content as return html
-			$endofpre = (stripos($html,'</pre>',$pos) === false ? strlen($html) : stripos($html,'</pre>',$pos));
+			if (($endofpre = stripos($html, '</pre>', $pos)) === false)
+			{
+				$html2ret[] = substr($html, $pos);
+				break;
+			}
 			$length = $endofpre-$pos+6;
 			$html2ret[] = substr($html,$pos,$length);
 			$searchFor = '<pre ';