diff --git a/CRM/Utils/Mail/Incoming.php b/CRM/Utils/Mail/Incoming.php
index 12e97e50125f..f0d580c570c3 100644
--- a/CRM/Utils/Mail/Incoming.php
+++ b/CRM/Utils/Mail/Incoming.php
@@ -92,7 +92,7 @@ public static function formatMailPart($part, &$attachments) {
       return NULL;
     }
 
-    CRM_Core_Error::fatal(ts("No clue about the %1", array(1 => get_class($part))));
+    return self::formatMailUnrecognisedPart($part);
   }
 
   /**
@@ -126,7 +126,7 @@ public function formatMailMultipart($part, &$attachments) {
       return self::formatMailDeliveryStatus($part);
     }
 
-    CRM_Core_Error::fatal(ts("No clue about the %1", array(1 => get_class($part))));
+    return self::formatMailUnrecognisedPart($part);
   }
 
   /**
@@ -248,6 +248,15 @@ public function formatMailDeliveryStatus($part) {
     return $t;
   }
 
+  /**
+   * @param $part
+   *
+   * @return string
+   */
+  public function formatUnrecognisedPart($part) {
+    return ts('Unrecognised message part of type "%1".', array('%1' => get_class($part)));
+  }
+
   /**
    * @param $part
    * @param $attachments