This is driving me nuts. In the CM CSS guide, it's pointed out that width is not supported (box model) for Outlook: http://www.campaignmonitor.com/css/
Indeed, despite my best efforts, a newsletter I'm trying to send it is stretching 100% in the Outlook window, when it should be sticking to 600px max (as stated in the CSS in multiple instances throughout the newsletter).
Having looked at other emails in Outlook though, these seem to be constrained without issue.
How do I go about constraining my whole newsletter to 600px in Outlook if box model width is not supported?
Found the solution. Simply a matter of using style="width:600px;" instead of width="600px;"
Hopefully this can save someone else a lot of trouble in the future.
When using width= you don't include the "px".
<table width="600" cellpadding="0" cellspacing="0" border="0"> <tr> <td width="600"></td> </tr> </table>