Re: Office 365 SharePoint 2013 App Assemblies

Hi Chris,

Thanks for your post here.

However the issue is out of our support scope, I suggest you try troubleshooting the issue via the steps below:

1. What version of Office 365 you’re using now? If it’s a subscription of purchased Office 365 and not be upgraded to the newest Office 365 yet, then a SharePoint 2013 App can’t be deployed on the Office 365 version, since SharePoint Online in the version is based on the 2010 version.
2. I suggest you post the issue to our develop forum via Developing Apps for SharePoint 2013 forum, thus our SharePoint Developing experts will help you investigate the issue, and provide you further solutions with more experiences, thanks for your understanding.

For more details, please refer to the links below:

 SharePoint for developers

 SharePoint Online for Office 365: Developer Guide

 Building apps for SharePoint and Office 365(currently available for Office 365 Preview)

 Getting Started with SharePoint Development