Table of Contents
Summary
- Auto Archiving for Exchange Online will automatically move the oldest items to the archive when a primary mailbox exceeds 96% of its quota.
- This feature will apply to both IPM folders and Recoverable Items folders, and it will respect “Never Move to Archive” tags.
- The archive mailbox must be provisioned and have available space for auto-archiving to occur.
- No immediate action is required, but administrators can adjust or disable the feature if desired.
- The change is categorized as a new feature and will impact administrators managing Exchange Online mailboxes.
Admin Impact: Medium
User Impact: Medium
Release Start: 01 Jan 2026
Release End: 31 Jan 2026
Services: Purview, Exchange
Category: Plan for change
Tags: New Feature, Admin Action
History
12/3/2025 Item Added to Message Center
Microsoft Message
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
Auto-archiving in Exchange Online | Microsoft Learn
Compliance considerations
No compliance considerations identified, review as appropriate for your organization.