How to archive email when your mailbox is full

Mailbox almost full? Standard Stack Hosting mailboxes include 10 GB (more if you have upgraded). When the mailbox is full, new messages bounce and are not queued. Free space below, or move older mail onto your Mac or PC.

Use this guide when a Stack Hosting mailbox is near its limit. IMAP mail that stays in server folders (Inbox, Sent, and so on) counts toward the quota. Mail you move into a local archive on your computer does not.

Jump to: Free space quickly · Apple Mail (Mac) · Outlook on Windows · Outlook for Mac · Webmail download

1. Free space quickly (do this first)

Empty Trash / Deleted Items. Deleted mail still uses quota until Trash is emptied for good.
Empty Spam / Junk on the server (webmail or your app).
Remove large attachments or old mail from Sent if you no longer need copies. That does not remove mail from recipients’ inboxes.
Check usage in your Stack Hosting control panel under email, or sign in to webmail (link on our Email & webmail page).

2. Archive with Apple Mail on your Mac

Create a local mailbox under On My Mac, then Move messages into it. Mail downloads to your Mac and leaves the Stack Hosting server, so it no longer counts toward quota.

Use Move, not Copy. Copying leaves a server copy (still using quota). Mail under “On My Mac” lives only on that Mac. Back the Mac up (Time Machine or similar) if you need to keep the archive.

Create an On My Mac archive mailbox

Open Apple Mail.
Choose Mailbox → New Mailbox….
Set Location to On My Mac (not your Stack Hosting / IMAP account).
Name it clearly, for example Archive 2024 or Stack Hosting archive.
Click OK. The mailbox appears under On My Mac in the sidebar.

Move old mail into the archive

Open the server folder that is full (Inbox, Sent, or another IMAP folder under your Stack Hosting account).
Select the messages (click one, then Shift-click for a range, or Command-A to select all in that view).
Control-click (or right-click) → Move To → your On My Mac archive. You can also drag the messages onto that mailbox.
Wait until Mail finishes. Large batches can take several minutes. Keep the Mac awake and online.
Empty Trash and Junk on the Stack Hosting account so deleted server copies leave the quota.

Repeat for other folders as needed. Archive oldest mail and large attachments first.

3. Archive with Outlook on Windows (classic Outlook)

In classic Outlook (the version with a File menu), create a local .pst data file and move older messages into it. That keeps a searchable archive on your PC and frees space on the server.

Open classic Outlook → File → Info → Account Settings → Account Settings.
Open the Data Files tab → Add… → create an Outlook Data File (.pst). Name it (for example Stack Hosting Archive) and save it somewhere you back up, such as Documents or an external drive.
In the folder list, open your Stack Hosting IMAP inbox (or other folder).
Select older messages, then drag them into a folder inside the new .pst, or right-click → Move → the archive folder.
Empty Deleted Items / Trash on the IMAP account. Compact the data file if Outlook offers that option.

You can also use File → Info → Tools → Clean Up Old Items / AutoArchive (wording varies by version) to move older mail on a schedule. Confirm messages are in the local .pst before you rely on them.

Using new Outlook on Windows? Local PST archiving is limited. Switch to classic Outlook for this, or archive with another IMAP app, then empty Trash on the server.

4. Archive with Outlook for Mac

Current Outlook for Mac does not use Windows-style .pst files. The most reliable way to keep a local copy and free server space is to add the same mailbox to Apple Mail and follow those steps.

If you want an Outlook export as well:

Open Outlook on your Mac.
Choose File → Export.
Export to an .olm file and save it somewhere you back up.
Confirm the .olm file is on disk, then delete the old messages from the IMAP account and empty Deleted Items.

An export alone does not free quota. You still have to remove the messages from the server.

5. Optional: download copies from webmail

In webmail (open it from our Email & webmail page) you can select messages → More → Download (for example Mbox) to keep a local zip. Downloading does not free quota. You must still delete or move those messages off the server and empty Trash.

6. Need more than 10 GB permanently?

If you always need a large live mailbox, increase storage from your Stack Hosting account:

Sign in at cp.stackhosting.uk/manage.
Open your package → Email Accounts (or mailbox usage).
Upgrade the mailbox or add extra storage in 10 GB blocks where offered.

Archiving locally is still useful after an upgrade. It keeps the live mailbox lean and the copies under your control.

Checklist

Confirm messages are in the local archive (On My Mac, Outlook .pst, or your .olm export).
Empty server Trash and Spam.
Send yourself a test message to confirm new mail is accepted.
Keep a Mac or PC backup of the archive.