Exchange databases cannot be backed up by using either a third-party backup solution, or the NT Backup application. When you back up an Exchange database, you may receive the following Application event log:
Event Type: ErrorEvent Source: ESE BACKUPEvent Category: (5)Event ID: 904Date: <date>Time: <time>User: N/AComputer: <servername>Description:Information Store (2264) Callback function call ErrESECBPrepareInstanceForBackup ended with error 0xC7FE1F45 Instance not found.
Additionally, the Exchange databases cannot be mounted.
The drive where the transaction log files are saved is full.
To resolve this issue, remove un-needed log files to another disk drive to free disk space.
Refer to the following Microsoft Knowledge Base article for instructions: For more information, click the following article number to view the article in the Microsoft Knowledge Base:
240145 How to remove Exchange Server transaction log files
328794 How to protect Exchange data from hard disk failure