Saturday, January 16, 2010

Resolving Exchange Error: “Database requires log files that could not be located.”

Transaction logging is a disaster recovery procedure of Microsoft Exchange Server that helps the database to get restored in consistent state after any unexpected stop. When the database stops suddenly, it goes to inconsistent state. On next restart, Exchange Server locates and then scans the log files to apply them from the database file. But for any reason if it fails to locate those log files, the recovery attempts fail. This forces you to locate the missing log files manually. However, if it cannot be accomplished, you need to restore the database from a suitable backup or perform Exchange Server Recovery using appropriate database repair procedures.

For each event in Exchange Server, the application logs the associated entry in Windows Application log. So, you might encounter the following error message displaying in this application log, usually after unexpected stop:

"Database requires log files that could not be located. The database requires log files to continue. Make sure the log files exist. Check Event logs for more information."

The event ID of this error in 453 and can cause database to become unmountable.


Exchange database needs some log files that it could not locate to continue. For further information on which log files could not be located, you can see the event description which mentions the sequence of log files that it could not locate. It also includes the log file number, up to which recovery has been possible.

Some prime reasons that might prevent log files from being located are:
1. The temporary folder doesn't contain the log files. The transaction logs are missing.

2. An anti virus software is running that has quarantined the log file 3. A hardware failure that has caused log files to lose. 


You need to apply these measures to solve the existing problem:

1. Check if the required log files have been moved. If yes, move them back to the correct folder. But if they have been deleted, you need to restore from the backup.

2. You need to stop the antivirus scanning if any and examine its registry settings to put back the current log files to correct folder.

3. If none of the above measures work, you should restore the database from the backup or apply eseutil repair (hard recovery) utilities to repair the database. Eseutil hard recovery is not safe to use as it deletes the corrupted pages. Thus, you are suggested to use commercial Exchange Recovery utilities as a better option. The Exchange Recovery software are suitable choice to repair corrupted Exchange database using safe, yet effective, scanning algorithms.

Exchange Recovery Software is a powerful EDB Recovery tool that repairs corrupted Exchange database and restores the mailboxes in *.pst files. The Microsoft Exchange Recovery tool supports MS Exchange Server 5.5, 2000, and 2003. The software is easy to install and operable using simple steps that even a non-tech user can understand.

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