Microsoft has introduced the all new Hybrid Migration Troubleshooter, which was first introduced during Microsoft Ignite in Chicago.
Why did they create this troubleshooter?
The Hybrid style of Mailbox move is one of the most popular and complex types of migration strategies. This option gives you a way to move some of their mailboxes to Exchange Online, while keeping some on-premises. It is also the only option that allows for your mailboxes to be off boarded using the native toolset. It is because of that complexity that Microsoft have seen many customers confused when trying to determine why there migration is failing, appears slow, or stalled.
The solution to this problem is for you to run the Hybrid Migration Troubleshooter from Http://aka.ms/HMTSEmail
Thank you goes to the following folks that made this possible:
Jeremy Kelly, Brad Hughes, Brad Craig, Scott Roberts, Padmini Palanki, and Timothy Heeney