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There can be several mailboxes in a single Exchange database consisting of inbox, outbox, contacts, calendar, and other folders for each account. At the same time, by the addition of information in these mailboxes, the size of the database increases. But when the user deletes some content from mailboxes, it does not create a free space for new data. Let’s say that you remove 4GB of data from the 30GB Exchange database, the expected size of the database should be 26GB. But, after removing the data, you will notice that the size remains the same, which is 30 GB. However, there would still be 4 GB of space available to add new data. This ‘Available new mailbox size’ is commonly known as White Space.

More about White Space

Although Microsoft professionals suggest that this is not the right term to describe this space, most individuals consider it as White Space, as it is available but not visible. White Space is the free space area in Exchange databases, which is created after the deletion of an item or object (like a mailbox). The White Space is reused by the Exchange database to store new items and objects. However, it will not be visible, as said above. But, you can reclaim this space manually by removing the white space.

How to find White Space in Exchange?

If you’re familiar with Exchange management shell and PowerShell commands, then there are three ways to find the white space in Exchange Database. You can use the below commands to find white space.

  1. To check white spaces on a mailbox database, use:
    Get-MailboxDatabase < DB Name > -status | Select-Object Server,Name,AvailableNewMailboxSpace
  2. To check white spaces on all mailbox database on a server, use:
    Get-MailboxDatabase –Status –Server < servername > | Select-Object Server,Name,AvailableNewMailboxSpace
  3. To check white spaces on all mailbox database on all server, use:.
    Get-MailboxDatabase -status | Select-Object Server,Name,AvailableNewMailboxSpace
Manual method to remove White Space in Exchange

Talking about the manual methods, there is only one way to remove white space from the Exchange database by using Defragmentation. Now, this process can be carried out online and offline. Below, we have covered both methods in detail.

  • Online defragmentation: Online database defragmentation process is entirely automatic. You do not need to initiate it; Exchange will automatically run it every night. However, online defragmentation does not reduce the size of the database – it remains same. It removes the expired messages. It also cleans up deleted mailboxes on mailbox store. To reduce the size of the database, you should go for Offline defragmentation.
  • Offline defragmentation: Offline database defragmentation helps in reduce the size of Exchange database. Using this process, you can compact the size of the database by eliminating the unused storage space. This process creates a new database having no empty pages (it replaces the older ones with the new ones or deletes the older ones). You can perform defragmentation by use Eseutil facility. This process improves the efficiency of Exchange database. But you can do this only when you have large amount of free space.
Defragmentation of Exchange Database

You can easily defrag the White Space in exchange database with a simple process, which we have described below.

  1. Before starting defrags process, you should ensure that how much amount of white space is available in Exchange database with the below command in Exchange Management Shell.
    Get-MailboxDatabase < Database name > -Status | Format-List Name, DatabaseSize, AvailableNewMailboxSpace
  2. Now after checking you have to dismount your Exchange database.
    Dismount-Database < database name >
  3. Once you have dismounted Exchange database, defragment the databae
    Eseutil /d < database_name >
  4. Now run the defrag the dismounted database and mount the database again.
    Mount-Database < database name >
  5. After all the steps check the white space available in your database after defragmentation.
    Get-MailboxDatabase < Database name > -Status | Format-List Name, DatabaseSize, AvailableNewMailboxSpace
Other Exchange Server issues

Apart from its large size, Exchange Database can be affected by many other issues including EDB file corruption. A corrupt EDB file becomes inaccessible to its users. So, the EDB files needs to be repaired at the earliest. But you can try third-party Exchange Server recovery tools to fix such issues. Kernel for Exchange Server is an efficient tool in fixing all Exchange related issues including corruption.


White Space is an abnormality in Exchange Server that hinders the creation of available space for new data in the database. If White Space has been increased substantially and stops to accommodate new data, then you can use the defragment to claim such space. The problem with offline defragmentation is that it can affect the structure of the database and cause some deletion too. To overcome corruption and deletion-related issues, you can use Kernel for Exchange Server software and recover mailbox from EDB file. It will scan the offline EDB file and bring all the mailboxes present in it. it also helps you to save the recovered data directly to a Live Exchange account.

Kernel for Exchange Server