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.

Cause

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. 

Solution

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.

Inconsistent Database Backup when Exchange Server is Running

Exchange Server databases are consisted of .edb files (database files) and .log files (database logs). All the transactions that occur for Exchange databases are first written to .log files before actually been written to database files. A database is inconsistent if all transaction log files have not been committed to the database files. But if you shut down the information service, Exchange writes all the log files to .edb files and the database comes to a completely consistent state. Thus, if you backup the database while information service is running, it will not be consistent. If your EDB files become corrupt and you try to restore from such a backup, it will give errors and the information service might fail to start. This creates an unavoidable situations of using an EDB Repair solution for your corrupted database files.

For example, consider your Exchange database files are corrupted. When you try to start Exchange Server services after restoring from a backup, you may encounter the below error in application log or on screen:


“Error -550 has occurred”

You cannot start the Exchange Server services.

Cause

You have used the backup software when Exchange Server was online. As a result, the backup is inconsistent and has failed to perform successful restore.



Solution


To prevent such errors from occurring, you are suggested to perform the database backup after stopping all the directory and information store services. Alternatively, you can look for backup solutions that are exclusively built to perform Exchange databases' backup in online state.

However, to recover the data from corrupted database files, you need to use these tools:

1. Eseutil /r command to perform soft database recovery
2. Eseutil /p command for hard repair
3. Third-party EDB Repair Tool

The hard recovery option of Exchange deletes the corrupted pages, which is not safe. Thus, you should use EDB Repair utilities if soft recovery fails. These software bring you the most effective and safe scanning algorithms for repairing damaged Exchange databases. Due to the interactive user interface they provide, these applications are easy to implement

EDB Repair Software is a feature-rich utility that employs powerful scanning algorithms to repair a damaged Exchange database. It supports Exchange Server 5.5, 2000 and 2003. It is a safe and advanced EDB Repair Tool with impressive set of features. The tool extracts user mailboxes in individual .pst file format files without affecting the original contents and view.

How to Solve when Exchange Database Fails to Mount with (hr=0x80004005, ec=-528) Error?

Transaction log files record all the modifications to an Exchange Server database and are crucial for the proper functioning of Exchange. If you remove a log file that has not been written to the associated database, it can bring several issues, the most common being that the database may fail to mount. You can solve this problem by removing all the log files, but you first need to check the database consistency. If it exists in inconsistent state, the solution is to restore from backup or apply an EDB Repair technique. For instance, consider a scenario in Exchange Server. You try to mount a mailbox store, but the operation fails with the below error message.