Exchange Online and unlimited archiving (Auto Expanding Archives)

Exchange Online and unlimited archiving (Auto Expanding Archives)

Microsoft has released new feature in Exchange online. It is Auto expand archiving.

When archive mailbox quota reached to it’s limit (100 GB), additional space automatically assigned to Archive mailbox.

When we enable archiving on a mailbox, 100 GB automatically assigned to Archive mailbox.

Now if auto expand is enabled on user mailbox and archive mailbox size reached to 90 GB then additional space automatically assigned to user archive mailbox. Afterwards additional space automatically keeps adding when requires.

Note: Auto-expanding archiving also supports shared mailboxes. To enable the archive for a shared mailbox, an Exchange Online Plan 2 license or an Exchange Online Plan 1 license with an Exchange Online Archiving license is required.

Outlook requirements for accessing items in an auto-expanded archive

To access messages that are stored in an auto-expanded archive, users have to use one of the following Outlook clients:

  • Outlook 2016 for Windows
  • Outlook on the web
  • Outlook 2016 for Mac

Note: Outlook 2013 won’t be able to access items that are moved to additional archive storage.

Auto-Expanding Archiving works with below exchange online feature:-

  • eDiscovery
  • Retention
  • Message Records management (MRM)
  • Import Service

How to enable Auto-expanding Archiving feature on Exchange online:-

You can enable Auto-Expanding archiving feature on User as well as on shared mailbox.

It can be enabled on organization or per user basis.

1. Enable auto-expanding archiving for your entire organization

When you enable it on organization level, all mailboxes gets this new feature (Archiving mailbox should be enabled for this feature to work).


Connect to Exchange online

Run below command:-

Set-OrganizationConfig -AutoExpandingArchive

To check if it is enabled run below:-

Get-OrganizationConfig | FL AutoExpandingArchiveEnabled

2. Enable auto-expanding archiving for specific users

You can enable auto-expand archiving feature on per user basis as well. User should have archive mailbox to get this new feature.

When you enable auto-expanding archiving for a specific user, the following two configurations changes are also made:

The storage quota for the user’s primary archive mailbox is increased by 10 GB (from 100 GB to 110 GB).

The storage quota for the Recoverable Items folder in the user’s primary mailbox is increased by 10 GB (also from 100 GB to 110 GB). This change is applicable only if the mailbox in on hold.


Connect to Exchange Online.

Run below command:-

Enable-Mailbox <user mailbox> -AutoExpandingArchive

To check if auto-expanding archiving status run below:-

Get-Mailbox <user mailbox> | FL AutoExpandingArchiveEnabled

Note:- User Archive mailbox must be enabled before running this command

Auto-Expanding Archiving only works in Exchange online. Both User primary as well as archiving mailbox should be on Exchange online.

After enabling auto-expanding archive it can take up to 30 days for the additional storage space to be provisioned.

Expansion only works when MFA (managed folder assistant runs). You can start MFA manually as well by running Start-ManagedFolderAssistant against mailbox.


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