When you perform operations like an online backup or defragmentation, the system reads each database page for writing or other processes. To do so, it first undergoes checksum test and check if it is correct. For any reason, if the page checksum mismatch with that has been calculated by database engine, it reports an error and the operation is halted. Such errors usually root from physical database corruption and compel you to restore the database from backup or apply some Exchange Repair measures to fix database corruption.
As an example of such problems, with Exchange Server 2007, you might exhibit the following symptoms:
1. The client computer cannot start Microsoft Outlook
2. Users fail to send/receive e-mails
3. Online backups and defragmentation fail with a -1018 checksum mismatch error
4. The application event log in Exchange Server reports an error as below:
“Database recovery and restore failed with an unexpected error.”
The above symptoms suggest that Exchange Server has failed to read database page due to checksum mismatch and the page is corrupt. However, the same issues can also occur due to firmware malfunction or problem in RAM. For the specific reason, you are suggested to view error code that is listed in the event description.
You need to apply these measures to solve the given problem:
1. If the error listed in event description is -515, the transaction log file(s) might be missing. Determine the missing logs and move them back to the log directory and/or restore the database from backup.
2. Check the system for hardware issues and solve them or migrate to a different hardware
3. Consider upgrading the BIOS and firmware
4. Perform Exchange Server Repair with eseutil /P command, followed by eseutil /D and isinteg -fix. Make sure you backup the database first as running this repair can cause important database pages to delete.
For safer MS Exchange Repair, consider using solutions like an Exchange Server recovery software. These commercial applications are built with advanced technology to run effective scan for a corrupted database and extract the valuable data out of it.
Exchange Repair Software is a professional utility that repairs corrupted Exchange Server databases. The Exchange Server Repair tool recovers all the mailboxes in individual *.pst files and also allows to select them as required. The tool supports Exchange Server 5.5, 2000, 2003, and 2007. The software can also recover deleted mailboxes.
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