Glossary
Exchange Archive
A secondary Exchange Online mailbox that extends storage beyond the primary mailbox limit for an individual user.
An Exchange Online archive mailbox is a secondary mailbox attached to a user's primary mailbox, extending storage beyond the 50 / 100 GB primary mailbox limit. Same user, accessed in Outlook as a separate folder tree. On plans that support it, auto-expanding archive grows up to 1.5 TB. Items can be moved to the archive automatically via the default Messaging Records Management (MRM) policy or manually by users. Different from Purview retention (compliance-driven preservation) and litigation hold (legal preservation). Archive is primarily a capacity tool for power users with very large mailbox histories. Searchable in Outlook and Purview eDiscovery just like the primary mailbox.