Microsoft plans larger auto-expanding archives for E5 mailboxes
Reviewed by Helen Jones
Office 365 IT Pros reports that Microsoft 365 roadmap item 560820 plans to raise the 1.5 TB auto-expanding archive limit for eligible Office 365 E5 and Microsoft 365 E5 mailboxes. Rollout is expected to start in October 2026, but Microsoft has not yet published the new limit, detailed licensing rules, or management changes.
Auto-expanding archives currently stop at 1.5 TB, and reaching that ceiling can eventually block more archive data from being stored. Tenants with unusually large retained mailboxes therefore need capacity monitoring and retention decisions rather than assuming the archive is unlimited. The planned increase may relieve immediate pressure for a small number of E5 tenants, but it does not remove the need to delete information that no longer has business or legal value. The missing limits and licensing detail also make this a watch item, not a change to design around yet.
Analysis
Identify E5 archive mailboxes approaching the current cap, but wait for the Microsoft 365 Message Center notice before changing retention or capacity plans. Confirm the new limit, eligible service plan, rollout date, and any management requirements first.
Source note
Pulse published by Collab365 Spaces, reviewed by Helen Jones on . Cite as "Microsoft plans larger auto-expanding archives for E5 mailboxes", Collab365 Spaces. 1 source referenced.