%1 (%2) %3The backup has been stopped because it was halted by the client or the connection with the client failed.

Details
Product:	Windows Operating System
Event ID:	215
Source:	ESENT
Version:	5.2
Symbolic Name:	STOP_BACKUP_ERROR_ABORT_BY_CALLER_INSTANCE_ID
Message:	%1 (%2) %3The backup has been stopped because it was halted by the client or the connection with the client failed.

Explanation
The most frequent cause of the error is that a third-party online Exchange-aware backup software program has problems. Other known causes are a checksum mismatch (corruption) in the database, losing the connection between the backup client and the Exchange server, and manually ending the connection between the backup client and the Exchange server.

User Action
Make sure that the backup software agent has not lost network connectivity to the Exchange server. If so, restart the database backup. Make sure logging of the backup software is enabled. Examine the logs of the backup software. Check the Web site of the backup software vendor to see if this is a known issue and whether a patch or hotfix is available. Use NT Backup to try the backup. If that backup succeeds, the backup software is causing the problem, and the issue needs to be referred to the backup software vendor. Check the Application log to make sure there are no database errors, and check the System log for hardware errors.