What is an Archive Mailbox in Exchange and Office 365?
An Archive mailbox in Exchange and Exchange online is a secondary mailbox storage where the emails from the primary user’s mailbox are moved and stored as a backup. It is also known as In-Place Archive and eliminates the need to create frequent PST backups. They also allow users to search emails and play an important role in retention and storage. One of the benefits of Archive mailboxes is that they help in decluttering the primary mailbox and make older emails searchable without having to delete emails from time to time.
Archive mailboxes or the facility for an In-Place Archive was introduced in Exchange server 2010 SP1 and enabled users to move their emails and mail data from their primary mailbox to a secondary storage. The Archive mailbox is stored in the Exchange database file (EDB) and is accessible from the Exchange server. You can create rules to move the emails to archive or use retention policies in the Exchange admin center (EAC) to automatically archive the emails after a specific period.