How to archive emails in Outlook

How to archive emails in Outlook: select them and click Archive (or press Backspace); the messages move to the Archive folder and stay searchable. AutoArchive, in classic Outlook under File → Options → Advanced, moves old items to a separate .pst file instead, and Online Archive is a second mailbox your administrator turns on. For a copy that lives outside Outlook altogether, save the email as a .msg file and convert it to a PDF in SaveMail; the file stays on your device.

What archive does in Outlook: three features with one name

Most confusion about Outlook archiving comes from one word meaning three things. The Archive button tidies the inbox. AutoArchive shrinks the mailbox. Online Archive adds storage. None of them makes a copy; each one moves the mail somewhere else.

Have the email as a file (EML, MSG, MBOX)? Convert it to PDF in your browser: nothing is uploaded.

How to archive emails in Outlook with the Archive button

1. Select one or more messages in the list.
2. Click Archive on the Home ribbon (classic) or in the toolbar above the message (new Outlook and web), or press Backspace.
3. The first time, classic Outlook asks which folder to use and offers to create one named Archive. Accept it.

The messages now sit in the Archive folder in the folder pane. Search still finds them, replies still thread, and the mailbox size has not changed. This is the right tool for "done with this, keep it out of sight," not for freeing space. Gmail users will recognize the behavior; the Gmail archive guide compares the two.

Set up AutoArchive in classic Outlook

AutoArchive moves items older than a cutoff into a file named archive.pst and deletes them from the mailbox. It exists only in classic Outlook for Windows.

1. Click File → Options → Advanced.
2. Under AutoArchive, click AutoArchive Settings.
3. Check Run AutoArchive every N days and set the interval.
4. Set Clean out items older than, for example 6 months.
5. Choose Move old items to and note the path of the .pst file; the default is inside your Documents\Outlook Files folder.
6. Click OK. To run it once right now, use File → Info → Tools → Clean Up Old Items.

Per-folder rules override the global ones: right-click a folder → Properties → AutoArchive tab. After the first run, an "Archives" account appears in the folder pane; that is the .pst file, opened. Back it up, because it is a single file on one disk, and a .pst file cannot be opened without Outlook.

How Online Archive works and how to enable it

Online Archive is a second mailbox attached to a Microsoft 365 or Exchange account. It shows up in the folder pane as "Online Archive - your@address" in classic Outlook and as "In-Place Archive" on the web. Mail moved there leaves your primary mailbox quota and stays on the server, searchable from Outlook but not synced to phones.

• Enabling it is an administrator action in the Microsoft 365 admin center or Exchange admin center; it needs a license that includes archiving. Users cannot switch it on themselves.
• Moving mail there is a drag from your inbox to a folder in the archive mailbox, or a retention policy that moves items older than a set age automatically (the default policy moves items after two years).
• Assigning a policy to a folder: classic Outlook, right-click folder → Properties → Policy.

If the archive mailbox is missing after your administrator enabled it, restart Outlook; it can take a day to appear.

Does archiving save space in Outlook?

Only AutoArchive and Online Archive do. The Archive button moves mail between folders in the same mailbox, so your quota does not change. To see where space goes, use File → Info → Tools → Mailbox Cleanup, which shows folder sizes and finds large messages. Large attachments are the usual culprit: saving them to disk and deleting them from the message frees far more than archiving.

Archive outside Outlook: a copy you control

Every Outlook archive lives in Outlook's formats and depends on the account staying active. For correspondence you may need after you leave a job, close an account or hand a matter to someone else, keep a copy as ordinary files.

1. Drag the emails from classic Outlook into a folder on disk; each becomes a .msg file with its attachments inside.
2. Drop a file on savemail.app to read it or press Save as PDF for a searchable PDF with the headers, including Message-ID, and the attachment list. The file is parsed in your browser; nothing is uploaded.
3. Store the .msg files, PDFs and attachment ZIPs together, named by date.

The email archiving guide covers naming, folder structure and what to keep for legal or tax purposes.

Frequently asked questions