The problem As you might know, Site Definitions are not supported on Office365. This is not a restriction of Office365 as such, but more a Sandboxing restriction. In a SharePoint 2010 Sandboxed environment you’re not allowed to deploy files to the file system. And a SharePoint Site Definition requires that. The answer lies in the newly introduced web template tag. In this post I will describe, step by step, how to create a web template, and how to create a new Site Collection based on that web template. ......