From: Ken Wong Ken on
When OOB approval workflow is configured on a sharepoint List or Document
Library, there is an option to set Due Date Reminder workflow.

"Due Date
If a due date is specified and e-mail is enabled on the server, participants
will receive a reminder on that date if their task is not finished."

In our setup the reminder emails sent out are received as unformatted text.
All other workflow notification emails are received as formatted.

Unformatted email text below:
----------------------------------------------
:
content-class: MSWorkflowTask
Content-Transfer-Encoding: 8bit
x-sharing-itemid: 45
x-sharing-remote-uid: {2E92DA64-98F2-4D10-A825-D8D1169F53B4}
Content-Type: text/html; charset=utf-8
Subject: Task assigned to Doc Approvr on 12/3/2009 is overdue.
x-sharing-wssbaseurl: http://myportal/mysite
MIME-Version: 1.0
X-Mailer: Windows SharePoint Services (version 3)

<style>
TABLE.mail { border-style:none; border-collapse:collapse; font:8pt Tahoma;
width:100%; }TD.header { background:#F8F8F9; border:1px solid #E8EAEC;
padding:12pt 10px 4pt 10px; }TD.body { padding:12pt 10px 24pt 10px;
}TD.footer { border-width:1px; border-style:solid none none none;
border-color:#9CA3AD; padding:4pt 10px 4pt 10px; }A { text-decoration:none;
}DIV.title { font:16pt Verdana; }DIV.headertext { margin:5px 0px 0px 0px;
}DIV.error { font-weight:bold; }DIV.comment { color:#9CA3AD; }SPAN.wfname {
font:bold italic; }
</style><table cellpadding="2" cellspacing="0" class="mail" DIR="none">
<tr class="header">


Config Details :
---------------------------

MOSS 2007 with SP1

We tried the hotfix http://support.microsoft.com/default.aspx/kb/937906 but
it does not seem to fix the issue.

Thanks in Advance