Remove utf8 encoding from email subject, mod a few other things if possible

I was after the same fix... as it turns out, most of the spam filters reject the emails from Drupal if they have the garbage subject lines, and I was unable to use Drupal until I got it fixed (as no one would ever get their registration/password emails, welcome emails, etc.). Thanks to the clue above and the correct code (above) help, I was able to find and fix it. Now my group loves Drupal. :)

For you non-programmers, the file is "modules/user.module". At line 246 (in ver 4.4.2, other versions may be a different line number), update the user_mail_encode() function so it looks like this:

function user_mail_encode($string, $charset = "UTF-8") {

  /*

  ** Used to encodes mail headers that contain non US- ASCII

  ** characters.

  ** http://www.rfc-editor.org/rfc/rfc2047.txt

  **

  ** Notes:

  ** - The chunks come in groupings of 4 bytes when using base64

  ** encoded.

  ** - trim() is used to ensure that no extra spacing is added by

  ** chunk_split() or preg_replace().

  ** - Using \n as the chunk separator may cause problems on some

  ** systems and may have to be changed to \r\n or \r.

  */

  if (!preg_match('/^[\x20-\x7E]*$/', $string)) {

    $chunk_size = 75 - 7 - strlen($charset);

    $chunk_size -= $chunk_size % 4;

    $string = trim(chunk_split(base64_encode($string), $chunk_size, "\n"));

    $string = trim(preg_replace('/^(.*)$/m', " =?$charset?B?\\1?=", $string));

  }

  return $string;

}

As always, the brackets and punctuation are critical, make sure they are exact. Save the file and run Drupal, and you'll find the subject lines come thru just fine.

Hope this helps.
Cheers!