Microsoft Purview: Auto-expanding archive capacity increases to 3 TB for eligible mailboxes

Microsoft Purview increases auto-expanding archive capacity for eligible Exchange Online mailboxes from 1.5 TB to 3 TB starting mid-October 2026. No extra configuration or charges apply. Administrators should verify license eligibility, monitor growth, and update documentation accordingly. Compliance impact is minimal.

[What and why]

Microsoft Purview Data Lifecycle Management is increasing the maximum auto-expanding archive capacity for eligible Exchange Online archive mailboxes from 1.5 TB to 3 TB. This enhancement helps organizations retain and manage larger volumes of archived email content without requiring manual archive expansion processes or support requests. Eligible mailboxes with auto-expanding archiving enabled will continue to grow automatically as needed.

[Rollout schedule]

• General Availability (Worldwide): Beginning in mid-October 2026 and expected to complete by late October 2026

[Impact on your organization]

Who is affected

• Organizations using Exchange Online archive mailboxes with auto-expanding archiving enabled
• Administrators responsible for Microsoft Purview Data Lifecycle Management and Exchange Online archiving
• Users assigned eligible licenses that support the increased archive capacity

Platforms and services

• Microsoft Purview Data Lifecycle Management
• Exchange Online
• Exchange Online Archiving

What will happen

• Eligible archive mailboxes with auto-expanding archiving enabled can automatically expand beyond the current 1.5 TB limit up to a maximum of 3 TB per mailbox.
• No additional configuration is required for eligible mailboxes that already have auto-expanding archiving enabled.
• No per-GB consumption charge is introduced as part of this change.
• Existing archive content, retention configurations, policies, and holds are unchanged.
• No new administrator workflow, user experience, or user interface is introduced.
• Mailboxes that do not have an eligible license will continue to be limited to 1.5 TB.

Eligible licensing includes:

• Office 365 E5, A5, and G5
• Microsoft 365 E5, A5, and G5
• Microsoft 365 Purview Suite
• Microsoft 365 Purview Suite FLW, EDU, and GOV
• Microsoft Defender + Purview Suite FLW
• Microsoft 365 F5 Compliance
• Microsoft 365 F5 Security + Compliance
• Combination of the eDiscovery & Audit and Insider Risk Management mini suites together with the Information Protection & Governance mini suite

Note: The maximum auto-expanding archive capacity supported through this feature is 3 TB per mailbox for eligible licenses.

[Action required and recommendations]

No action is required if eligible mailboxes already have auto-expanding archiving enabled.

We recommend that administrators:

• Review license assignments for users with large archive mailboxes to confirm eligibility.
• Monitor archive mailbox growth using Exchange Online PowerShell.
• Identify mailboxes approaching their applicable archive capacity limits.
• Update internal documentation, retention guidance, and help desk materials to reflect the new 3 TB limit.
• Review licensing and retention strategies for users whose archive mailboxes are not eligible for the expanded capacity.

Learn more

• Enable auto-expanding archiving | Microsoft Learn
• Learn about auto-expanding archiving | Microsoft Learn

[Compliance considerations]

No compliance considerations identified. Review as appropriate for your organization.