Defrag Exchange Mailbox Database Using PowerShell Cmdlets

Updated On - July 12, 2023 by Savita Sharma |

Reading Time: 4 minutes

Exchange Mailbox Databases are essential Exchange Server components that store all your email data. Over time, as the database grows and changes, it can become fragmented, which can negatively impact performance. Defragmenting the database helps to reorganize the data making it more efficiently stored, and can improve the overall speed and reliability of your Exchange Server. In this blog post, we will explore how to defrag an Exchange Mailbox Database using PowerShell cmdlets. We’ll provide a step-by-step guide to help you efficiently and effectively defragment your database, so you can keep your Exchange Server running smoothly.

More About Exchange defragment/Whitespace

Whitespace in an Exchange Server refers to the unused disk space within a mailbox database. This space is created when an item within the database is deleted or modified, leaving behind an empty space where the previous item was stored.

Over time, the accumulation of Whitespace within the database can slow down Exchange Server. Make it more difficult for the database to efficiently store new data. By reclaiming this Whitespace, the database can be optimized to improve performance.

In Exchange Server, you can reclaim Whitespace by using the “Clean-MailboxDatabase” cmdlet in PowerShell, which will defrag Exchange mailbox database and reclaim any unused space. It’s important to regularly monitor and reclaim Whitespace within your Exchange Server to ensure optimal performance and reliability.

How to Find White Space in MS Exchange Server?

To find the amount of White space in an Exchange Mailbox Database, you can use the “Get-MailboxDatabase” cmdlet in PowerShell. This cmdlet retrieves information about the mailbox databases in your Exchange Server environment. You can filter the output to show only the mailbox database you want to inspect and then use the “DatabaseSize” property to see the total size of the database and the “AvailableNewMailboxSpace” property to see the amount of White space.

Here’s an example command:

Get-MailboxDatabase -Identity "Mailbox Database Name" | Select-Object DatabaseSize, AvailableNewMailboxSpace

This command will show you the total size of the mailbox database and the amount of available White space, so you can determine whether reclaiming White space is necessary. Keep in mind that the amount of White space can fluctuate over time, so it’s a good idea to regularly check and reclaim White space in your Exchange Server environment.

Ways to defrag Exchange Server mailbox

Online Defragmentation: This process can be carried out while the database is in use, and it will not interrupt normal operations. The online defragmentation process is initiated through the “Start-MailboxDatabaseMaintenance” cmdlet in PowerShell, as shown in the example below:

Start-MailboxDatabaseMaintenance -Identity "Mailbox Database Name"

This command will start the online defrag Exchange mailbox database process, which will reclaim any unused space within the database.

Offline Defragmentation: This process requires that the database be taken offline, which means that users will not be able to access their mailboxes while the process is being carried out. Offline defragmentation is performed using the “eseutil /d” command in the Exchange Management Shell. The syntax of the command is as follows:

eseutil /d "path\to\database.edb"

This command will start the offline defragmentation process, which will reclaim any unused space within the database.

Exchange 2010: How to Defragment the Mailbox Database

Defragmentation of Exchange mailbox database is accomplished with the help of the Eseutil software, which is launched via the PowerShell command line. If you’re comfortable with the command prompt, you won’t have any trouble using it; otherwise, you might get stuck. There are two options for cleaning up your database of extra spaces.

Step 1: – Defragment an Exchange 2010 Database

The mailbox database can only be defragmented if it is first dismounted. This means that the user’s email will be unavailable during the defragmentation process.

Second, remember that defragmentation requires free space on the disk that is at least 1.1 times the size of the new file’s estimated size. A new file will be created during this process, and both files will exist simultaneously, so if the necessary disk space is not available, you will need to specify a different temporary location, which can be on another local drive or a UNC path, and the defragmentation process will take longer because of network latency.

Step 2: Defragment the Exchange 2010 mailbox database using Eseutil

Launch Exchange Management Shell and navigate to the directory containing the database, as shown in the path below.

Defragment the mailbox using the Eseutil program as follows: cd D: Data mailbox name>Eseutil /d mailbox.edb file /t testserverdefragtemp.edb> Dismount the mailbox database using the command Dismount -Database database name

Note: – A complete backup of this Database is strongly suggested right away.

The Database should be remounted onto the server using the command mount-database database name.

By rerunning the command first employed to ascertain white space, it is now apparent that all white space has been eliminated, and Exchange 2010 has been defragmented.

You may check the status of your mailbox with the following command:

Get- MailboxDatabse -Status | ft name, databsesize, availablenewmailboxspace -auto.

It’s important to note that both online and offline defragmentation processes can be time-consuming. It’s recommended to schedule them during periods of low user activity.

Use Professional Automated tool to resolve Exchange issues

Regain EDB to PST Converter is a professional tool, designed to convert EDB files to PST files. This tool can be used to resolve various Exchange-related issues, such as data corruption, mailbox loss, and others.

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Here’s how you can use the Regain EDB to PST Converter to resolve Exchange issues:

  1. Download and install the tool on your computer.
  2. Launch the tool and select the Exchange EDB file you want to convert.
  3. Preview the contents of the selected EDB file.
  4. Select the desired output format (PST) and specify the location where you want to save the converted file.
  5. Start the conversion process.

The Regain EDB to PST Converter can recover your Exchange data and save it to a desired format. Once the conversion process is complete, you can access your Exchange data in Microsoft Outlook. This can be useful if you’re unable to access your Exchange data directly due to corruption or other issues.


Defragmentation is an important process that helps to optimize Exchange Mailbox Databases and ensure their optimal performance. The manual method of defragmentation involves using PowerShell command in the Exchange Management Shell. However, this process can be time-consuming and resource-intensive, and scheduling it during periods of low user activity is recommended.

Apart from this, Regain EDB to PST Converter software can resolve various Exchange-related issues. And also recover Exchange data and saves recover data in desire format.

Regular monitoring of the White space amount can help you identify potential performance issues and resolve them before they become major problems.

Author: Savita Sharma

I am Savita Sharma Technical Consultant and Writer in Regain Software. My responsibility in company is to update website with latest information regularly. And adding new content to make information easy and understandable. Usually writing on almost all products of Regain Software.

One thought on “Defrag Exchange Mailbox Database Using PowerShell Cmdlets”

  1. Avatar Paul Jackson says:

    I was looking for a way to defragment my Exchange mailbox database using PowerShell cmdlets, and this was really helpful. For online defragmentation, I have used the mentioned script, but it doesn’t work for me. However, the offline defragmentation script easily worked for me.

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