Mailbox Archive
This article outlines archive mailboxes and the auto-expanding features.
Run Diagnostics
Run an automated diagnostic check on a user's archive mailbox to identify any problems and suggested resolutions.
PowerShell
Connect-ExchangeOnline
Enable-Mailbox -Identity <username> -Archive
Auto-expanding
Enable-Mailbox <user mailbox> -AutoExpandingArchive
Get-Mailbox <user mailbox> | FL AutoExpandingArchiveEnabled
