inbox email does not show “From” or “Subject”, message is garbled

I belong to a "yahoogroup". I receive about 100 messages every day from the group.  Within the past few weeks, 1-5 messages each day come to Windows Live in the wrong format.  

1. No "From"  

2. No "Subject"

3. the message itself is garbled coding.

I contacted the yahoogroup moderator and he replied that there is nothing wrong with my account.  I checked my email on my ISP server (cox.net) and all of the yahoogroup messages are completely correct there.  This means that Windows Live is the cause of the problem.

Here is a partial example of a message I received today.

--9nlWnTS9ocNmxdhsK3FKVLWiM6a5jwOaA8HvrLV
Content-Transfer-Encoding: base64
Content-Type: text/plain; charset="UTF-8"

Rm9yIFNhbGUsIGxhcmdlIGJyaWxsaWFudCBDcnlzdGFsIENoYW5kZWxpZXIsIHBlcmZlY3QgZm9y
IHRoZSBoaWdoIGNlaWxpbmcgZm95ZXIgb3IgZm9ybWFsIGRpbmluZyByb29tLiAgTG90cyBvZiBi
ZWF1dGlmdWwgcHJpc21zIGFuZCBjcnlzdGFscywgY2FuZGxlc3RpY2sgc3R5bGUuDQogDQoNCiBS
ZXRhaWxzIGZvciAkNDk5IHRvICQ2OTkuICANCiANCg0KIEFza2luZyAkMTUwLiAgQ2FzaCwgKG5v
IGNoZWNrcyBwbGVhc2UpLiANCiANCg0KIFBlcmZlY3QgY29uZGl0aW9uLCBvbmx5IGRvZXNuJ3Qg
Zml0IG15IGRpbmluZyByb29tLg0KIEFscmVhZHkgdG8gdGFrZSBhd2F5LCBib3hlZC4gICANCiAN
Cg0KIENhbGwgQ2Fyb2xpbmUgUnlrZXIgYXQgNjIzLTM5OC03ODYwIHRvIGFycmFuZ2Ugdmlld2lu
ZyBhbmQgcGlja3VwLg0KIA0KDQogDQogDQoNCg==

--9nlWnTS9ocNmxdhsK3FKVLWiM6a5jwOaA8HvrLV
Content-Type: text/html; charset=UTF-8
Content-Transfer-Encoding: 7bit

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
</head>

<body style="background-color: #fff;">
<span style="display:none">&nbsp;</span>

<!--~-|**|PrettyHtmlStartT|**|-~-->
<div id="ygrp-mlmsg" style="position:relative;">
  <div id="ygrp-msg" style="z-index: 1;">
<!--~-|**|PrettyHtmlEndT|**|-~-->

    <div id="ygrp-text" >
     
 
      <p><span><p><span>For Sale, large brilliant Crystal Chandelier, perfect for the high ceiling foyer or formal dining room.&nbsp; Lots of beautiful prisms and crystals, candlestick style.</span></p><div><br></div><div>Retails for $499 to $699.&nbsp; </div><div><br></div><div>Asking $150.&nbsp; Cash, (no checks please). </div><div><br></div><div>Perfect condition, only doesn&#39;t fit my dining room.</div><div>Already to take away, boxed. &nbsp; </div><div><br></div><div>Call Caroline Ryker at&nbsp;623-398-7860 to arrange viewing and pickup.</div><p><b></b><i></i><u></u><strike></strike><br class="yui-cursor"></p></span><p></p><p><span><br class="yui-cursor"></span></p></p>

    </div>
    

    <!--~-|**|PrettyHtmlStart|**|-~-->
    <div style="color: #fff; height: 0;">__._,_.___</div>
 
 
    <div style="clear:both"> </div>

    <div id="fromDMARC" style="margin-top: 10px;">
        <hr style="height:2px ; border-width:0; color:#E3E3E3; background-color:#E3E3E3;">
        Posted by: *** Email address is removed for privacy ***        <hr style="height:2px ; border-width:0; color:#E3E3E3; background-color:#E3E3E3;">
     </div>
    <div style="clear:both"> </div>

    <table cellspacing=4px style="margin-top: 10px; margin-bottom: 10px; color: #2D50FD;">
      <tbody>
        <tr>
          <td style="font-size: 12px; font-family: arial; font-weight: bold; padding: 7px 5px 5px;"  >
                          <a style="text-decoration: none; color: #2D50FD" href="https://groups.yahoo.com/neo/groups/pebblecreek/conversations/messages/279392;_ylc=X3oDMTJyYmJnNGlmBF9TAzk3MzU5NzE0BGdycElkAzEyNjYxNzMEZ3Jwc3BJZAMxNzA1MDQzOTY3BG1zZ0lkAzI3OTM5MgRzZWMDZnRyBHNsawNycGx5BHN0aW1lAzE0NTc4MjM2MTE-?act=reply&messageNum=279392">Reply via web post</a>
                      </td>
          <td>&bull;</td>
          <td style="font-size: 12px; font-family: arial; padding: 7px 5px 5px;" >
            <a href="mailto:*** Email address is removed for privacy ***?subject=Re%3A%20Crystal%20Chandelier%20For%20Sale" style="text-decoration: none; color: #2D50FD;">
               Reply to sender            </a>
          </td>
          <td>&bull;</td>
          <td style="font-size: 12px; font-family: arial; padding: 7px 5px 5px;">
            <a href="mailto:*** Email address is removed for privacy ***?subject=Re%3A%20Crystal%20Chandelier%20For%20Sale" style="text-decoration: none; color: #2D50FD">
              Reply to group            </a>
          </td>
          <td>&bull;</td>
          <td style="font-size: 12px; font-family: arial; padding: 7px 5px 5px;" >
            <a href="https://groups.yahoo.com/neo/groups/pebblecreek/conversations/newtopic;_ylc=X3oDMTJlODYxc2U1BF9TAzk3MzU5NzE0BGdycElkAzEyNjYxNzMEZ3Jwc3BJZAMxNzA1MDQzOTY3BHNlYwNmdHIEc2xrA250cGMEc3RpbWUDMTQ1NzgyMzYxMQ--" style="text-decoration: none; color: #2D50FD">Start a New Topic</a>
          </td>
          <td>&bull;</td>
          <td style="font-size: 12px; font-family: arial; padding: 7px 5px 5px;color: #2D50FD;" >
                            <a href="https://groups.yahoo.com/neo/groups/pebblecreek/conversations/topics/279392;_ylc=X3oDMTM4Z2xhZXAyBF9TAzk3MzU5NzE0BGdycElkAzEyNjYxNzMEZ3Jwc3BJZAMxNzA1MDQzOTY3BG1zZ0lkAzI3OTM5MgRzZWMDZnRyBHNsawN2dHBjBHN0aW1lAzE0NTc4MjM2MTEEdHBjSWQDMjc5Mzky" style="text-decoration: none; color: #2D50FD;">Messages in this topic</a>
                (1)
                      </td>
        </tr>
      </tbody>
    </table>