New Outlook auto-archiving springs into action when your mailbox hits 90% capacity Existing archiving and data retention policies remain unaffected Auto-expanding archives are also on the horizon Microsoft will soon start rolling out new threshold-based auto-archiving for Exchange Online in a bid to prevent ‘mailbox full’ errors. The feature will work by automatically archiving the oldest items when storage capacity reaches capacity, marking a change from time-based archiving (like ‘move after