Quick answer: Sign in to the Exchange admin center as an admin, go to Recipients > Mailboxes, select the user, open the Others tab and choose Manage mailbox archive. Switch the archive on and save. In PowerShell, run Enable-Mailbox -Identity [email protected] -Archive. The archive then shows up in Outlook as Online Archive, which can take a few hours.
Applies to: Microsoft 365 and Office 365 business plans with Exchange Online. You need an Exchange or Global administrator role; users can’t turn on their own archive.
In this guide
What an archive mailbox is
An archive mailbox, also called an online archive or In-Place Archive, is extra cloud storage attached to a user’s mailbox. It keeps old mail out of the main mailbox so that the main mailbox doesn’t fill up, without the user having to manage local PST files. Most business plans include a 50 GB archive, and plans such as Microsoft 365 E3 and E5 can grow it automatically. Check your own plan before you rely on a specific size.
Once the archive is on, Exchange Online’s default retention policy moves items older than two years into it automatically, unless your organization uses a different policy.
Enable the archive in the Exchange admin center
- Go to the Exchange admin center at
admin.exchange.microsoft.comand sign in with an admin account. - Select Recipients > Mailboxes.
- Select the user’s mailbox. In the details pane that opens, select the Others tab.
- Under Mailbox archive, select Manage mailbox archive.
- Turn the archive on and select Save. The mailbox list then shows the archive status as active.
To enable several users at once, tick them in the mailbox list and use the archive option in the toolbar, if your admin center shows it; otherwise use PowerShell below.
Enable archives with PowerShell
Connect to Exchange Online PowerShell first (Connect-ExchangeOnline from the ExchangeOnlineManagement module), then run one of these:
# One user
Enable-Mailbox -Identity [email protected] -Archive
# Every user mailbox that doesn't have an archive yet
Get-Mailbox -Filter {ArchiveStatus -Eq "None" -AND RecipientTypeDetails -eq "UserMailbox"} -ResultSize Unlimited | Enable-Mailbox -ArchiveTo check the result, run Get-Mailbox [email protected] | Format-List ArchiveStatus,ArchiveName. To turn an archive off again, use Disable-Mailbox -Identity [email protected] -Archive, but be careful: Microsoft only keeps the contents of a disabled archive for a limited time before they’re permanently removed.
Turn on auto-expanding archiving
If a user’s archive is close to full and your licences support it, you can let it grow beyond the standard size. For one user, run Enable-Mailbox -Identity [email protected] -AutoExpandingArchive. For the whole organization, run Set-OrganizationConfig -AutoExpandingArchive. This can’t be turned off once it’s enabled, so check Microsoft’s licensing notes first.
Where the archive appears in Outlook
After the archive is created, it appears in the folder pane as Online Archive – [email protected] in classic Outlook, and as In-Place Archive or Archive in new Outlook and Outlook on the web. It can take a few hours to appear. Users can drag mail into it like any other folder. Nothing needs to be added by hand. If you also need a team inbox, see how to add a shared mailbox in Outlook.
Don’t confuse the online archive with the Archive folder inside the main mailbox. That folder is just a normal folder that the Archive button moves mail to, and it still counts against the main mailbox quota.
If the archive doesn’t show up
- Give it time: new archives can take several hours to appear, and Outlook needs to be restarted.
- Classic Outlook in cached mode: make sure the account is an Exchange account, not IMAP or POP. If you use a very old Outlook version, update it or try the current classic Outlook.
- Licence: check that the user has a licence that includes Exchange Online archiving.
- Wrong account: if the user has several mailboxes, the archive only appears under the mailbox it belongs to.
Related guides
- How to add a shared mailbox in Outlook
- Outlook tips and tricks
- How to recall an email in Outlook
- Outlook classic download: how to get it back
Official sources:
- Microsoft Learn: Enable archive mailboxes for Microsoft 365
- Microsoft Learn: Enable auto-expanding archiving
Frequently asked questions
Can a user enable their own archive mailbox?
No. An admin has to turn it on in the Exchange admin center or with PowerShell. Users can only move mail into it once it exists.
Does the archive count against the mailbox size?
No. The archive has its own storage quota, separate from the main mailbox.
Can I archive a shared mailbox?
Yes, but a shared mailbox usually needs a licence that includes Exchange Online archiving before you can enable its archive.
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