Article ID: 2608489 - View products that this article applies to.
A user is not able to access a mailbox that resides on a particular database after a restart of the Microsoft Exchange Information Store service on a Microsoft Exchange 2010 Server.
A mailbox database on this server is not configured to mount upon startup of the Microsoft Exchange Information Store service.
For more information on this topic, see the following document from Microsoft TechNet online:
Mailbox store will not mount on startup
(http://go.microsoft.com/fwlink/?LinkId=151500)for other considerations.