Topic Last Modified: 2008-07-17
When a database is mounted, Microsoft Exchange Server 2007 validates a globally unique identifier (GUID) in the Microsoft Exchange Information Store (MSExchangeIS) with an entry stored in Active Directory directory service. The Microsoft Exchange Information Store service cannot be started if these two GUIDs do not match. Mismatches can occur if the database has been restored from an offline backup.
When these GUIDs do not match, a "patch" is performed automatically by Store.exe when the database is mounted. In earlier versions of Exchange, you had to run the Isinteg -patch command after you restored a database from an offline backup. However, you don't have to run the Isinteg -patch command in Exchange 2007.
For a description of the Isinteg tool, see Microsoft Knowledge Base article 182081, Description of the Isinteg utility.
For information about the Isinteg command-line parameters, see Microsoft Knowledge Base article 301460, Exchange Command-Line Parameters for the Isinteg.exe Tool.
How the Patch Operation Works
For the patch operation to complete successfully, the database must be set to allow being overwritten by a restore procedure. Set the This database can be overwritten by restore attribute by running the following Exchange Management Console command:
set-mailboxdatabase <database_name> -AllowFileRestore:$true
If the database is not set to be overwritten and the Information Store requires a patch operation to start, this information store will not start, and the following event will be written to the Event Viewer application log:
Event ID: 1087
Source: MSExchangeIS Mailbox
Description: The information store was restored from an offline backup. In the Exchange Management Console, indicate that the database can be overwritten by a restore, so that it can be patched.
If the This database can be overwritten by a restore attribute is set and the database requires a patch operation, Store.exe automatically patches the information store upon startup and the following event is written to the Event Viewer application log:
Event ID: 9524
Description: The Information Store database <DatabaseName> was restored from an offline backup - it has been patched. Please back up this database.
After Store.exe performs a patch against a database, clients logging on to that database may encounter a slight slowdown when loading the client for the first time after installing the patch. Installing the patch resets the per-user read/unread GUID on this store, and forces all clients to reload their per-user read information from this database.
For More Information
For general information about the Isinteg tool, see Isinteg.
For more information about tools that are used with Exchange Server, see Tools for Troubleshooting.
For an overview of the tools required specifically to assist with disaster recovery, see Disaster Recovery Tools and Wizards.
For information about running the cmdlet that enables the database to be overwritten by a restore procedure, see Set-MailboxDatabase.