Index: includes/mail.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/mail.inc,v
retrieving revision 1.28
diff -u -r1.28 mail.inc
--- includes/mail.inc	2 Nov 2009 04:10:51 -0000	1.28
+++ includes/mail.inc	25 Nov 2009 04:08:22 -0000
@@ -121,11 +121,14 @@
     // To prevent e-mail from looking like spam, the addresses in the Sender and
     // Return-Path headers should have a domain authorized to use the originating
     // SMTP server. Errors-To is redundant, but shouldn't hurt.
-    $headers['From'] = $headers['Sender'] = $headers['Return-Path'] = $headers['Errors-To'] = $default_from;
+    $headers['Sender'] = $headers['Return-Path'] = $headers['Errors-To'] = $default_from;
   }
   if ($from) {
     $headers['From'] = $from;
   }
+  elseif ($default_from) {
+    $headers['From'] = '"' . str_replace('"', '', variable_get('site_name', 'Drupal')) . '" <' . $default_from . '>';
+  }
   $message['headers'] = $headers;
 
   // Build the e-mail (get subject and body, allow additional headers) by