[Introduction]
We’re introducing Auto Archiving for Exchange Online to help prevent mail flow disruptions caused by mailboxes reaching their storage quota. This update ensures real-time mailbox health monitoring by automatically moving the oldest items to the archive when mailbox usage exceeds 96% of its quota. This feature addresses customer feedback for proactive mailbox space management and helps maintain business continuity.
[When this will happen:]
- Public Preview: Rollout began in mid-November 2025 and is expected to complete early December 2025
- Worldwide rollout: Rollout begins in early January 2026 and is expected to complete late January 2026
[How this affects your organization:]
Who is affected: Admins managing Exchange Online mailboxes with provisioned archive mailboxes.
What will happen:
- When a primary mailbox exceeds 96% of its quota, Managed Folder Assistant will automatically archive the oldest items until usage drops below the threshold.
- Applies to both IPM folders and Recoverable Items folders.
- Honors Never Move to Archive tags.
- Enabled by default for all tenants.
- Archive mailbox must be provisioned and have available space for auto-archiving to occur.
[What you can do to prepare:]
- No immediate action is required unless you want to adjust or disable this feature.
- To disable auto-archiving for a mailbox:
Set-Mailbox <user-smtp-address> -AutoArchivingEnabled $false
- To adjust the organization-level threshold (default = 96%, valid range = 80–100):
Set-OrganizationConfig –AutoArchivingThresholdPercentage <value>
- If set to 100, auto-archiving will not occur for the tenant.
- Review internal documentation and communicate this change to helpdesk staff.
Learn more:
[Compliance considerations:]
No compliance considerations identified, review as appropriate for your organization.