Microsoft Purview | Data lifecycle management – Auto archive for Exchange Online

Auto Archiving for Exchange Online automatically moves oldest mailbox items to archive when usage exceeds 96%, preventing mail flow disruption. Enabled by default, it applies to mailboxes with archives, respects “Never Move to Archive” tags, and allows admin adjustments or disabling. Rollout starts January 2026. 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. Auto-archiving in Exchange Online | Microsoft Learn Message ID: MC1191923

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