How to archive email on a Mac

What the Archive button does

In Apple Mail and in Outlook, “Archive” moves a message from the inbox into a folder called Archive. On an IMAP account that folder lives on the server, next to all the others. The message can still be changed, moved and deleted there, from any device with access to the account, and nothing records it.

That is useful for keeping an inbox empty. It is not an archive in any legal sense.

Why Time Machine is not an archive

Time Machine backs up the Mac, and with it the copy Apple Mail keeps of your messages. As an archive it falls short for several reasons:

• Time Machine thins out older backups and deletes the oldest when the backup disk is full. It will not reliably hold ten years.
• A message that arrives and is deleted between two backups was never backed up.
• Nothing shows that a restored message is unchanged.
• You do not search ten years of mail; you search backup by backup.

You still need a backup, of the archive too. It just does not replace one.

Exporting a mailbox: a copy, not an archive

Apple Mail exports a mailbox as an .mbox package with Mailbox ▸ Export Mailbox; Outlook for Mac exports an archive as an .olm file. That is a good one-off copy. It captures nothing going forward, proves nothing about whether the copy is unchanged, and can only be searched across years once it has been read back in.

Such exports are, however, exactly right for bringing older mail into an archive.

What an archive has to do

For businesses in Switzerland and Germany, the Code of Obligations and the GeBüV, and the HGB, AO and GoBD, ask essentially the same:

• Complete: captured continuously, not only when somebody remembers.
• Unchanged: or any change is noticed.
• Findable: within a reasonable time, even after years.
• Readable: until the period ends, if need be without the software it was archived with.
• Erasable where required: under the GDPR, once no duty remains.
• Checked: regularly, by a person who stands behind it.

Exactly how long is set out in the overview of the regimes.

Setting it up with MailVault

1. Download MailVaultThe app is notarised by Apple and runs on macOS 14 or later. To the download
2. Create an archiveName, location and the regimes that apply to you. If you need to erase under the GDPR, choose it now.
3. Connect the mailboxesMicrosoft 365 and Outlook.com through Microsoft's sign-in, Gmail with an app password, any other account over IMAP.
4. Bring in older mailApple Mail's mailbox folder, exported .mbox packages, Outlook files (PST, OST, OLM) or a Thunderbird profile.
5. Let it collect automaticallyDaily at a fixed time suits most; if people delete a lot, collect more often.
6. Record the second copy and the procedural documentationWhere the archive's backup lives and where the procedural documentation is kept, under Retention Policy ▸ Organisation. The template for the documentation is there too.
7. Run the first controlA deep verification, as a dated report a person signs.

And the space on the server?

Many people archive to free up space on the server. MailVault deletes nothing on the server, not even after a collection. Whether you tidy the mailbox afterwards is your decision. Verify the archive deeply first, and bear in mind that only what was collected before it was deleted is in the archive.