If your inbox lives entirely on a mail server, you’re one outage, one account lockout, or one accidental “delete all” away from losing years of correspondence. The good news: IMAP email backup on a Mac doesn’t require special software or technical know-how. Apple Mail, built into every Mac, can do the job on its own.
The Easiest Method: Export Mailboxes with Apple Mail
The simplest way to back up IMAP emails locally on a Mac is to use Apple Mail’s built-in export feature, which saves your messages as .mbox files on your hard drive.
Steps:
- Open Mail and make sure your IMAP account is added and fully synced (check the sidebar for a syncing spinner — let it finish).
- Select the mailbox or folder you want to back up. To back up everything, select all folders under your account (Cmd+click to select multiple).
- Go to Mailbox > Export Mailbox… in the menu bar.
- Choose a destination folder — an external drive or a dedicated “Mail Backups” folder is a smart choice.
- Click Choose. Mail will create an
.mboxpackage containing your messages, attachments, and folder structure.
That’s it. The exported .mbox files are readable by Apple Mail, Thunderbird, and most other mail clients, so you’re not locked into one app to access them later.
Building an Offline IMAP Email Archive on Mac
For a more thorough offline IMAP email archive, a few extra habits make the backup more durable:
- Repeat exports on a schedule. IMAP servers change constantly, so a one-time export only captures a snapshot. Set a recurring reminder (monthly or quarterly) to re-export.
- Back up to more than one location. Copy your exported
.mboxfolder to both a local external drive and a cloud storage folder (iCloud Drive, Dropbox, etc.) for redundancy. - Include attachments. Apple Mail’s export includes attachments by default, but double-check file sizes look right — a folder with almost no size for years of email usually means attachments were stripped or not downloaded before export.
- Verify the backup. Open the
.mboxfile in Mail (File > Import Mailboxes) on a test basis to confirm messages are intact and readable.
Alternative: Third-Party Backup Tools
If you manage multiple IMAP accounts or want automated, incremental backups, dedicated tools add convenience:
- Letter Opener / IMAPCopy / getmail — command-line tools for advanced users who want scripted, repeatable backups.
- Mail Backup X or EmailBackup — Mac apps built specifically for scheduled IMAP backups, with search and restore features.
- Time Machine — if you’re using Apple Mail as your client, Time Machine will already snapshot your local Mail data (
~/Library/Mail) as part of your regular system backups, though this isn’t a substitute for an independent export.
Featured Tool: MacSonik IMAP Backup Tool
For users who want more control than a simple .mbox export offers, MacSonik IMAP Backup Tool is a dedicated Mac (and Windows) utility built specifically for backing up and migrating IMAP email data.
Key capabilities:
- Multiple output formats — save IMAP emails locally as MBOX, PST, PDF, MSG, CSV, or other formats, rather than being limited to a single archive type.
- Direct migration options — move emails from an IMAP account straight into Gmail, Office 365, or another IMAP account, not just to a local file.
- Batch backups — back up single or multiple mailboxes, and multiple user accounts, in one run.
- Selective backup by date range — pull only the emails from a specific time window instead of the entire mailbox history.
- Attachment handling — choose to back up emails with or without attachments, or save attachments separately as PDFs while keeping the original folder structure intact.
- Duplicate removal — filter out identical emails (matched by sender, subject, or body) during the backup or migration process.
- PST splitting — break large output PST files into smaller, more manageable chunks.
A free version is available for testing (limited to 50 emails per folder); the full version unlocks unlimited backup, migration, and filtering features. It’s a solid option if you need format flexibility or want to migrate IMAP data into another email service rather than just archiving it locally.
Quick Comparison
| Method | Effort | Best for |
|---|---|---|
| Apple Mail export (.mbox) | Low | Most users, one-time or periodic manual backups |
| Time Machine | None (automatic) | General safety net, not a portable archive |
| MacSonik IMAP Backup Tool | Low–Medium | Multiple formats, migration to Gmail/Office 365, batch or filtered backups |
| Other third-party backup apps | Medium | Multiple accounts, scheduled/automated backups |
| Command-line tools | High | Power users, scripted workflows |
The Bottom Line
For most people, the easiest way to back up IMAP email locally on a Mac is Apple Mail’s Mailbox > Export Mailbox feature. It’s free, built-in, and produces a portable archive you can store anywhere. Layer in a recurring schedule and a second storage location, and you’ve got a reliable offline IMAP email archive without installing anything extra.
