The Exchange store is dismounted, and event ID 1159 is logged in Exchange Server 2007

In Microsoft Exchange Server 2007, the Exchange store is dismounted. Additionally, an event that resembles the following event is logged in the Application log on a server that is running Exchange Server 2007:

Event Type: Error
Event Source: MSExchangeIS
Event Category: General
Event ID: 1159
Description: Database error 0xfffffd9a occurred in function JTAB_BASE::EcUpdate while accessing the database" DatabaseName >".

Note The error code 0xfffffd9a translates to JET_errCheckpointDepthTooDeep.

This behavior occurs if the storage group that is related to the Exchange store contains more than 5000 uncommitted Extensible Storage Engine (ESE) transaction log files. Each ESE storage group has a hard-coded limit of 5120 uncommitted ESE transaction log files. When the number of uncommitted ESE transaction log files in an ESE storage group reaches 5000, Exchange Server 2007 starts to dismount the Exchange store in the storage group. Additionally, event ID 1159 is logged in the Application log.

To work around this behavior, restart the Microsoft Exchange Information Store service. To do this, follow these steps on the server that is running Exchange Server 2007:

1. Click Start, click Run, type services.msc, and then click OK.
2. In the Services list, right-click Microsoft Exchange Information Store Service, and then click Restart.
3. Close the Services dialog box.

This behavior is by design.

Many uncommitted ESE transaction log files may be created in the following scenarios:

• A process is locked in the backup software that you are using.
• The backup software that you are using stopped responding.
• You try to move many mailboxes at the same time that a backup process occurs.
• The server is experiencing performance issues. For example, disk subsystem issues are preventing the server from responding quickly to simultaneous disk-intensive operations.

To determine how many uncommitted ESE transaction log files are in the storage group, review the checkpoint depth.

The checkpoint depth is the difference between the location of the checkpoint file and the location of the E0x.log file. The checkpoint file lists transactions that were committed to the database. The checkpoint depth indicates how many ESE transaction log files contain content that is not yet committed to the Exchange store.