diff --git a/phpgwapi/inc/class.translation.inc.php b/phpgwapi/inc/class.translation.inc.php
index 998aeb7853..c677f81bdb 100644
--- a/phpgwapi/inc/class.translation.inc.php
+++ b/phpgwapi/inc/class.translation.inc.php
@@ -875,7 +875,8 @@ class translation
 				if ($element->charset != 'x-unknown')
 				{
 					if( strtoupper($element->charset) != 'UTF-8') $element->text = preg_replace($sar,$rar,$element->text);
-					if(preg_match('/\?=.+=\?/', $element->text))
+					// check if there is a possible nested encoding; make sure that the inputstring and the decoded result are different to avoid loops
+					if(preg_match('/\?=.+=\?/', $element->text) && $element->text != $_string)
 					{
 						$element->text = self::decodeMailHeader($element->text, $element->charset);
 						$element->charset = $displayCharset;