You have more than one Recovery Database (RDB) database on a Microsoft Exchange Server 2010 Mailbox server.
You unmount the first RDB database, and then mount another RDB database.
A user tries to access a mailbox in the mounted RDB database by using a MAPI application, such as MFCMAPI.
In this scenario, the user receives the following error message:
To resolve this issue, install the following update rollup:
2579150 Description of Update Rollup 4 for Exchange Server 2010 Service Pack 1
Note If the Exchange Server 2010 Mailbox server role and the Exchange Server 2010 Client Access server roles are installed on the same server, you must grant the View Information Store Status permission to the NetworkService account to install this update.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.