diff --git a/mozilla/mailnews/mime/src/mimehdrs.cpp b/mozilla/mailnews/mime/src/mimehdrs.cpp
index d52e760dc69..4b68cbdd880 100644
--- a/mozilla/mailnews/mime/src/mimehdrs.cpp
+++ b/mozilla/mailnews/mime/src/mimehdrs.cpp
@@ -75,7 +75,7 @@ MimeHeaders_convert_header_value(MimeDisplayOptions *opt, nsAFlatCString &value)
 
     if (converted)
     {
-      value = converted;
+      value.Adopt(converted);
     }
   }
   else