If transitioning your organization from a non-Exchange system such as Google or Lotus Notes to Office 365, you typically need to follow the IMAP migration path. As diagnosing and remediating any issues you might run into during such a migration can be difficult for people unfamiliar with the matter, we worked with our Support teams to provide some guidance for exactly such cases and packaged it for you in a wizard-like package.
Read more at source: http://blogs.technet.com/b/exchange/archive/2014/11/10/introducing-the-imap-migration-troubleshooter.aspx
