Single-bit error is a special case of CRC (Cyclic Redundancy Check) failure in Exchange Server database. The Error Detection Code or ECC that is included in the database page can fix such single-bit errors for a few (usually one or two) numbers. But if you experience single-bit error against a large number of database pages, the ECC doesn’t allow you to recover automatically. Such problems generally originate from hardware, firmware, or driver issues and is reported in the event log of server. You can address these problems by using a backup or applying Exchange EDB Recovery utilities.
Exchange single-bit errors are most likely to be reported while online backup or defragmentation. This is because while these operations, database is read at page-level and corruption also exists at page-level. For instance, you might encounter the below error message:
The database page read from the file ‘file_name’ at offset ‘offset’ (database page) for ‘number’ bytes failed verification. Bit ‘bit’ was corrupted and was corrected but page verification failed with error ‘error’. This problem is likely due to faulty hardware and may continue. Transient failures such as these can be a precursor to a catastrophic failure in the storage subsystem containing this file. Please contact your hardware vendor for further assistance diagnosing the problem.
This error is usually associated with -1018 error and is logged under event 398.
The error suggests that the specific database page that has been referenced in Exchange database file such as Priv.edb is damaged. It occurs when CRC of a database page mismatches with that contained in this page. Exchange reports a fatal error when there is a multibit error.
You need these measures to solve the given problem:
Perform all system diagnostic tests and take the corrective measures
Use a different set of hardware if required
Upgrade the firmware or BIOS to the latest versions available
Perform EDB Recovery using eseutil /P and eseutil /D commands
eseutil /P is an unsafe command with respect to database integrity as it deletes corrupted pages. However, if you use an EDB Recovery Software that proves much safer to repair the corrupted database and extract the lost data.
EDB Recovery Software is an efficient utility that repairs corrupted Exchange databases and restores the mailboxes in individual *.pst files. The EDB Recovery Tool also recover deleted mailboxes. The tool is compatible with Exchange Server 5.5, 2000, 2003, and 2007. The software recovers STM data in e-mail body.