Archiving and Unlimited Archiving in Office 365
Updated: Mar 11
In Microsoft 365, archive mailboxes refer to the additional mailbox storage space provided to users.
The primary intent for using archive mailboxes is for users to move data that they no longer use currently to a secondary mailbox. This helps save storage costs associated with the primary mailboxes.
First off, archiving is turned OFF by default and has to be turned ON by the administrator – for each mailbox individually. Once this is done, the archive shows up as if it were a separate folder in the user’s view within Outlook or Outlook on the web.
The archive size isn’t unlimited by default- it is set to 100GB at the start. But the administrator can choose to enable “auto-expanding archiving”. Once this is in place, when that archive folder reaches a 90% threshold, Office 365 automatically adds in additional space in the form of another archive folder.
After the archive mailbox is enabled, up to 100 GB of additional storage is available per user. Once the limit is reached, users can make use of a feature called auto-expanding archiving (also called unlimited archiving) that provides additional storage in the archive without contacting Microsoft. However, there is a limit of 1.5 TB to the auto-expanded archive.
Archive mailboxes act as a secondary mailbox that can be used to save up on storage costs on mailbox items that are no longer actively used.
License requirement
Archive mailboxes are available to all organizations that have an Exchange Online license.
Feature access
Archive mailbox settings are available under 'MRM',
Auto-application
The archive mailbox has to be enabled to use this feature. Once enabled, both admins and users can set it up to automatically move old messages to the archive.
Limits
Archive mailboxes can only be used to archive mails for a single user or entity (such as a shared mailbox) for which a license has been applied. Using archive mailboxes for storing mail from multiple users or entities is not allowed.
Storage quota
After the archive mailbox is enabled, up to 100 GB of additional storage is available per user. Once the limit is reached, Microsoft provides a feature called unlimited archiving where an extended archive gets added. However, the maximum limit after unlimited archiving is enabled is 1.5 TB per mailbox.
Level of application (item-level/container-level)
Specific mails, folders, or an entire mailbox can be archived.
Time for activation
The Managed Folder Assistant (MFA) periodically reviews items that are placed on retention and moves them to the archive mailbox if opted.
Deletion
Content in the archive if deleted, is permanently lost. However, if the auto-expanding feature in enabled, items cannot be deleted from the archive mailbox.
Auto Expand Archive
An Auto-Expanding Archive provisions more Archive storage space, if needed. Default Archives have 100 GB of storage available. If the archive is already bigger than 100 GB, we must have additional storage.
Usually, a user gets 100 GB of storage for archiving, when a mailbox capacity is reached, auto-expanding will add automatically additional storage, Office 365 automatically adds storage space to the archive when necessary, another important point it’s that auto-expanding adds additional space for shared mailboxes as well.
Once you turned on auto-expanding archiving for your mailbox it can take up to 60 days for getting the additional storage. BTW, almost forget to state – you cannot turn off auto-expanding as soon as you turn on it.
Before you turn on the “Auto-Expanding ” ensure you have enabled the archiving option to the user.
Once you turned on auto-expanding archiving for your mailbox it can take up to 60 days for getting the additional storage. BTW, almost forget to state – you cannot turn off auto-expanding as soon as you turn on it.
Before you turn on the “Auto-Expanding ” ensure you have enabled the archiving option to the user.