The M365 Online Archive is enabled for mailboxes near 100GB in size, over 50,000 mail items in a single folder, or have retention folders (hidden) nearing these limits. Enabling the archive will improve the performance of Outlook and keep the mailbox better organized. This process reduces the size and number of items in the primary mailbox by moving older messages to a separate archive mailbox. Below you will find some details about how to access and manage the archive mailbox.
- A few hours after Online Archive is enabled you will see a new folder appear in the Outlook client and when you're using the web version of Outlook. This folder will be labeled 'Online Archive - <username>' or 'In-Place Archive - <username>' respectively (see image below).
- Mail items are moved from the primary mailbox to the archive mailbox if they are one year or older than, 1. the date of delivery to the mailbox, or 2. the date you created the mail item.
- You can move items between the mailboxes and manage the Online Archive just as you would your primary mailbox, including searching for mail and replying from the Archive.
- This archive only functions on Outlook desktop clients and Outlook for the Web and is currently not available on Outlook Mobile apps. Those accessing email via iPhone/Android, Apple Mail, Thunderbird or any other mail client will be unable to see or access their archive.