If CKEditor is showing the HTML code when you go to edit text that has already been formatted, make the following change to the html_output.php file in the admin/functions directory.

Find:
} elseif (tep_not_null($text)) {
$field .= tep_output_string_protected($text);
}

Note: Attached file is empty

Replace with:

} elseif (tep_not_null($text)) {
$field .= $text;
}


More...