Buttons.cm is not working in MailChimp if you import your HTML by zip. It breaks the conditional statement by adding breaks and tabs, which results in displaying both buttons (the a and the mso one) in some Outlook versions (2007, 2010, ...). If you just copy paste the code in MailChimp there is no problem, it's just importing the buttons.cm code that breaks the code. I tried to contact MailChimp support but they are telling me I should contact the creators of buttons.cm (wich is Campaign Monitor). Any idea how to fix this?

http://i.imgur.com/5bYfvwJ.png

This is the code that I import:

<div><!--[if mso]>
  <v:rect xmlns:v="urn:schemas-microsoft-com:vml" xmlns:w="urn:schemas-microsoft-com:office:word" href="https://www.facebook.com/conceptfashionstore/photos/a.208877539124867.54837.200578996621388/1445184232160852/?lang=nl&utm_source=email&utm_medium=newsletter&utm_campaign=20170210_valentine_nl&utm_content=button02" style="height:40px;v-text-anchor:middle;width:220px;" strokecolor="#000000" fillcolor="#ffffff">
    <w:anchorlock/>
    <center style="color:#000000;font-family:sans-serif;font-size:14px;font-weight:bold;">VERRAS EEN SINGLE</center>
  </v:rect>
<![endif]--><a href="https://www.facebook.com/conceptfashionstore/photos/a.208877539124867.54837.200578996621388/1445184232160852/?lang=nl&utm_source=email&utm_medium=newsletter&utm_campaign=20170210_valentine_nl&utm_content=button02"
style="background-color:#ffffff;border:1px solid #000000;color:#000000;display:inline-block;font-family:sans-serif;font-size:14px;font-weight:bold;line-height:40px;text-align:center;text-decoration:none;width:220px;-webkit-text-size-adjust:none;mso-hide:all;">VERRAS EEN SINGLE</a></div>

This is what MailChimp does with it:

<div>
                                      <!--[if mso]>
                                      <v:rect xmlns:v="urn:schemas-microsoft-com:vml" href="https://www.facebook.com/conceptfashionstore/photos/a.208877539124867.54837.200578996621388/1445184232160852/?lang=nl&amp;utm_source=email&amp;utm_medium=newsletter&amp;utm_campaign=20170210_valentine_nl&amp;utm_content=button02" style="height:40px;v-text-anchor:middle;width:220px;" strokecolor="#000000" fillcolor="#ffffff">

                                        <center style="color:#000000;font-family:sans-serif;font-size:14px;font-weight:bold;">VERRAS EEN SINGLE</center>
                                      </v:rect>
                                      <![endif]-->
                                      <a href="https://www.facebook.com/conceptfashionstore/photos/a.208877539124867.54837.200578996621388/1445184232160852/?lang=nl&utm_source=email&utm_medium=newsletter&utm_campaign=20170210_valentine_nl&utm_content=button02" style="background-color:#ffffff;border:1px solid #000000;color:#000000;display:inline-block;font-family:sans-serif;font-size:14px;font-weight:bold;line-height:40px;text-align:center;text-decoration:none;width:220px;">VERRAS EEN SINGLE</a>
                                    </div>