Can't access Outlook Web App or Outlook during a database move or internal migration


When users try to access Outlook Web App or Outlook in Microsoft Office 365 Dedicated/ITAR, they receive the following error messages: 
  • In Outlook Web App: 
    You weren't able to sign in because the mailbox is being moved. You won't be able to access it until the move is complete. Please wait and try again later.
  • In Outlook:
    Cannot start Microsoft Outlook. Cannot open the Outlook window. The set of folders cannot be opened. Microsoft Exchange is not available. Either there are network problems or the Exchange server is down for maintenance.


This issue may occur if one or both of the following conditions are true:
  • The mailbox database was moved within the same environment.
  • There was an internal migration from one environment to another (for example, from Exchange Server 2010 to Exchange Server 2013).


The mailbox database move is triggered either by an internal process from one database to another through the MMT tool for load balancing (this may occur at any time) or by an internal migration.

The last stage of a mailbox move consists of the final delta sync to make sure that all data in the original mailbox is migrated. In this situation, users may not have access to their mailboxes for 2–5 minutes, but it may be longer for larger mailboxes. If a user reports a problem accessing their mailbox for longer than 15 minutes, escalate the incident to Microsoft for investigation.

Article ID: 3136658 - Last Review: Jan 20, 2016 - Revision: 1