Who This Affects and What It Does
This guide is for small-business employees whose organization uses Exchange Online (Office 365) and needs to enable auto-expanding archiving for one or more mailboxes. Activating this feature allows mailboxes to grow their archive storage automatically, but it does carry important considerations that must be reviewed before any changes are made, as enabling it can have unintended consequences for the future behavior of those mailboxes.
Before You Begin
Auto-expanding archiving is not a setting to enable without preparation. Microsoft’s own documentation includes disclaimers about how this change can affect mailbox behavior going forward. Read all disclaimers in any Microsoft documentation related to this feature before proceeding. If you have any concern or question about how this might interact with your planned workflows, stop and consult a qualified IT professional before continuing.
If you are unsure whether this is the right step for your organization, contact the ACS team for guidance before making any changes.
Steps to Enable Auto-Expanding Archiving
- Review all Microsoft-provided disclaimers and documentation on auto-expanding archiving for Office 365 before taking any action.
- Confirm that archiving is already enabled on the target mailbox or mailboxes, as auto-expanding archiving builds on an existing archive.
- Determine whether you need to enable auto-expanding archiving at the organization level (affecting all mailboxes) or for specific individual users only.
- Follow the steps in the official Microsoft documentation linked from your IT provider to run the appropriate commands for your chosen scope (organization-wide or per-user).
- After enabling the feature, note that it may take up to 30 days for the auto-expanding archive to be provisioned for a given mailbox, as described in Microsoft’s documentation.
- Document the change, including which mailboxes or the organization scope that was modified and the date the change was made.
Important Considerations
Once auto-expanding archiving is enabled, it cannot be disabled. This makes it critical to understand the full impact before proceeding. Changes at the organization level apply to all current and future mailboxes, while per-user enablement applies only to those specific accounts. Either way, the long-term mailbox behavior will be permanently altered.
If anything in this process is unclear or you have questions about how it applies to your Office 365 environment, reach out to Advanced Computer Solutions before making any changes.