So the issue with buttons that can occur in Marketo is when a knak email containing buttons is synced to Marketo and you go into the Marketo rich text area containing the button to make edits.
This causes changes to the code where a conditional comment is broken causing the email to break in most Windows versions of Outlook. The impacted button will look something like this:
That is obviously not where you want the button to be!
We are working on a robust solution to allow you to make edits in Marketo without the chances of this happening. In the mean time here are some ways to avoid this or to fix it if it occurs.
Edit emails in knak. The best way to avoid this entirely is to not edit the knak email from within Marketo. We hope knak provides you with the most flexible way to build emails so that your emails are ready to go as soon as you sync them. If you don't need to make any changes in Marketo then this issue won't happen! Plus if you do need to make edits then you can always go back to knak and use our re-sync functionality to make changes in seconds without any chance of breaking the code.
Minify the HTML. If the above options don't work for you and you are seeing the issue in Marketo then there is a simple cut and paste solution to resolve this. If you go to edit the area that contains the button that’s causing issues in Marketo.
You can then click on the HTML button to see the offending code that's causing the problem.
Then you can copy all that into an html minifier like this: http://minifycode.com/html-minifier/
That will remove the spaces in the code that's causing the button to look strange. You can then copy that back into the same place in Marketo, click apply and it should fix the issue.
We now have another option that we can enable in your account that should resolve the rendering issue. The solution is to simplify the button code so that Marketo does not break the email even when it adds line breaks. The solution does mean that the buttons will not have rounded corners in Outlook. Other than that they should render properly. If you want us to enable this option in your account then please do let us know.