An Exchange Server database can get corrupt for several reasons, which include database page checksum errors, B-Tree damage, table corruption and more. At this point, you should consider restoring from the latest backup or repairing the database by running Exchange utilities. At the last resort, you can use an Exchange Server Recovery solution.

For instance, suppose the Exchange Server starts Online Defragmentation on the database, but the process stops with an error as below:

"Online defragmentation of a database ended prematurely after encountering an unexpected error err_no. The next time online defragmentation is started on this database, it will resume from the point of interruption."

The error is logged with event 705 in application event log.

Cause

There can be several causes that generate event 705 and the exact root can be determined by the err_no displaying in the error code:

1. Err -1018= Jet_errReadVerifyFailure implies checksum errors on database page. This also indicates database corruption at ESE level. The general causes are file system issues, hardware problems or controller issues.

2. Error -1069 = Jet_errVersionStoreOutOfMemory indicates out of memory issues in Exchange store.

3. Error -327 = Jet_errBadPageLink and Error -338 = Jet_errBadParentPageLink imply bad page link in B-Tree of database. The errors indicate database corruption at Jet level.

Solution

In case of Jet_errVersionStoreOutOfMemory error, you need to contact the product support services. For the other two errors, you should try these steps:

1. You should check the application event log for hardware, controllers and file system related concerns and take the corresponding action.

2. If the database exists in running state, you can use ExMerge to extract the database as .pst files and later, export them in a new database after deleting the corrupted one. Alternatively, you can move the mailboxes to another store.

3. If the database is not running, you should immediately restore it from an online backup (if available). When there is no backup, you need to repair the corrupted database by running eseutil /p and isinteg -fix commands to repair it. If none of the measures work, you are suggested to use a third-party Exchange Recovery tool. An Exchange Recovery software retrieves data from a corrupted Exchange database by running suitable repair algorithms.

Microsoft Exchange Recovery Software is an advanced and safe tool that performs systematic database repair of damaged Exchange databases created with Exchange Server 5.5, 2000 and 2003. The tool can recover all email messages, journals, notes, tasks and other objects. It is a comprehensive Exchange Recovery tool that extracts all user mailboxes by converting them into individual Outlook usable .pst files.