Isinteg -patch is no longer required to restore offline backups

In Microsoft Exchange Server 5.5 and in earlier versions of Exchange Server, you must run the isinteg -patch command after you restore a database from an offline backup. However, you do not have to run the isinteg -patch command in Exchange 2000 Server or in Exchange Server 2003. During startup, Exchange 2000 or Exchange 2003 validates a globally unique identifier (GUID) in the information store with an entry stored in Windows 2000 Active Directory. The Exchange 2000 or Exchange 2003 information store cannot be started if these two sets of GUIDs do not match. Mismatches can occur if the information store has been restored from an offline backup. When these GUIDs do not match, a "patch" is performed automatically by Store.exe when the information store starts up.

For the patch operation to complete successfully, the database must be set to allow being overwritten by a restore procedure. To enable this setting, click to select the This database can be overwritten by a restore check box in the database properties in Exchange System Manager.

1. Start Exchange System Manager.
2. Click to expand Servers, click to expand the server on which the database is located, and then click Storage Group.
3. Right-click on the database, and then click Properties.
4. Click the Database tab.
5. Click to select the This database can be overwritten by a restore check box.

When you click this check box, it sets the Active Directory attribute, msExchPatchMDB, to a value of TRUE. This value is stored in Active Directory at the following location: If this check box is not selected (that is, if this value is stored as FALSE in Active Directory), and this information store requires a patch operation to start, this information store will not start, and the following event is written to the Event Viewer application log:

Event ID: 1087
Source: MSExchangeIS Mailbox
Type: Error
Description: The Information Store was restored from an offline backup. Indicate that the database is allowed to be restored to, in the Microsoft Exchange System Manager, so the database can be patched.

If the This database can be overwritten by a restore check box is selected 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
Source: MSExchangeIS
Category: General
Type: Warning
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 since the patch was performed. When a patch is performed, it resets the per-user read/unread GUID on this store, and forces all clients to re-load their per-user read information from this database.