Repair Exchange Database With ESEUTIL

Database corruption in Exchange Server is a common issue that can have severe implications on your organization, such as downtime and productivity loss, leading to financial losses. When a database goes down or dismounts due to corruption or inconsistencies, users cannot access their mail account or send/receive emails. However, Microsoft provides Extensible Storage Engine Utilities or EseUtil utility with Exchange Server 4.0 and later versions that administrators can use to repair inconsistent or corrupt databases. 

EseUtil is also used to maintain the Exchange database health by defragmenting, reducing the size, and running integrity checks on the mailbox database. In this guide, we will discuss the steps to repair and recover a corrupt or damaged Exchange database with the help of EseUtil.

EseUtil is a built-in command-line-based Exchange mailbox database recovery tool that you can run using the Command Prompt application. 

Follow these steps to repair the Exchange database using the EseUtil commands:

Step 1: Locate Database and Transaction Logs

Before using EseUtil to repair an inconsistent or corrupt Exchange mailbox database, you must know the database and transaction log files’ location. By default, Exchange Server stores the database at the following location,

C:\Program Files\Microsoft\Exchange Server\Vxx\Mailbox\<database>

While the transaction log files are stored at the following location,

C:\Program Files\Microsoft\Exchange Server\Vxx\Logging)

NOTE: The Vxx varies based on the Exchange Server version. 

Besides database and transaction logs, Exchange Server also creates checkpoint files, reserved logs, and temporary log files to maintain the database integrity. However, due to issues such as server crash, software or hardware failure, insufficient storage space, deleted or missing transaction logs, malware or virus intrusion, etc., the database gets damaged and enters an inconsistent or Dirty Shutdown state.
 

Step 2: Check Free Space

EseUtil requires free space equal to the size of the database. However, to calculate the correct free space required, check the database size and open the 1221 event ID to check the whitespace in the database. Then, subtract the whitespace from the database size- this is the minimum space required to perform database recovery using EseUtil. 

Step 3: Verify Database Status and Transaction logs’ Health

You also need to check the database status before repairing the database with EseUtil. The command to check database status is as follow,
eseutil /mh <path to database/database name.edb>
For instance, 
eseutil /mh C:\Program Files\Microsoft\Exchange Server\Vxx\Mailbox\DB01.edb

In the output, check the database state. If the State: Dirty Shutdown, the database is inconsistent or corrupt and requires repair. Also, check the log files’ health by running the following Command, 
eseutil /ml  C:\Program Files\Microsoft\Exchange Server\Vxx\Mailbox\DB01.edb

If the logs are healthy, the out will display “No damaged log files were found.” If so, proceed to the next step.
 

Step 4: Repair Exchange Database with EseUtil

You can run Soft Recovery using the EseUtil command to fix the database with minor corruption or damage due to uncommitted log files. In Soft Recovery, the EseUtil replays the uncommitted transaction logs on the database to commit the pending changes, which brings the database back into a Clean Shutdown state. The steps are as follow

• Login to Exchange Server as administrator and open Command Prompt 
• Run the Eseutil command and check the output. If it displays EseUtil is not recognized…., execute the following command to navigate to EseUtil location, cd C:\Program Files\Microsoft\Exchange Server\Vxx\Bin

• Ensure free space equal to the size of the database is available on the drive and then run the following command,
  ESEUTIL /r <log_prefix> /l <path_to_log files folder> /d <path_to_database folder> 
  Eseutil /r e01 /l " C:\Program Files\Microsoft\Exchange Server\Vxx\Mailbox" /d " C:\Program Files\Microsoft\Exchange Server\Vxx\Logging)”