I have an email that looks fine on all outlooks (03-2013) and web clients. But for some weird reason on Microsoft Outlook 2013 on a small laptop and tablet devices the width of the email shrinks smaller than the set width (of 600px in this case).
Hey there! It's possible that the mobile version of the email is being displayed when the screen size is reduced. You could try tweaking your media queries to account for that. I'm happy to take a look at your campaign, if you could drop an email to support with the details, we can help out!
This is possibly due to DPI scaling.