How to Archive IMAP Emails Locally on Mac & Linux

Your emails live on someone else's server. Every message you have ever sent or received through Gmail, Outlook, Yahoo, or any IMAP provider sits on hardware you do not control. If the provider changes its terms, shuts down a service, locks your account, or simply has a bad day, those emails could disappear. Most people do not think about this until it is too late.

Local email archiving solves this problem by downloading your emails from the server and storing them as files on your own computer. Once archived locally, your emails are yours — no internet connection required, no storage quotas, no dependency on any provider staying in business.

The Problem With Keeping Emails Only on the Server

IMAP is designed to keep emails synchronized between a server and your email client. That is convenient for everyday use, but it means the server is the single source of truth. If the server loses your data, you lose your data. Here are the most common risks:

• Storage limits — Free tiers on Gmail (15 GB shared with Drive and Photos), Outlook (15 GB), and Yahoo (1 TB) eventually fill up. When they do, you stop receiving new emails.
• Account lockouts — Forgotten passwords, two-factor issues, or policy violations can lock you out of your account permanently.
• Provider changes — Services shut down, merge, or change pricing. Google has retired dozens of products. Yahoo Mail has changed hands multiple times.
• No offline access — Without a local copy, you cannot search or read old emails without an internet connection.
• Compliance and legal — Some professions require you to retain emails for years. Relying on a third-party server for compliance is risky.

What Local Archiving Actually Means

When you archive an email locally, the app downloads the full message — headers, body, and all attachments — and saves it as a file on your disk. The email is no longer dependent on the server. You can read it, search it, forward it, or back it up to an external drive, all without touching the internet.

The format those files are stored in matters. Some email clients use proprietary databases that lock you into their software. If the client stops being developed, your archive becomes unreadable. The better approach is to use an open, standard format.

Why .eml and Maildir Matter

.eml is the standard file format for email messages, defined by RFC 5322. Every email client on every platform can open an .eml file. It is a plain-text format that contains the full message: headers, body (plain text and HTML), and MIME-encoded attachments. Because it is a standard, your archived emails are not locked into any specific software.

Maildir is a standard directory structure for storing email. Each message is a separate file in a well-defined folder hierarchy. Unlike mbox (which concatenates all messages into a single file), Maildir is resistant to corruption — if one file gets damaged, the rest of your archive is unaffected. It is also fast to search and easy to back up incrementally.

MailVault uses both: emails are stored as individual .eml files in a Maildir directory structure, organized by account and folder. This means your archive is just a folder full of standard email files that any tool can read.

How MailVault Archives Your Emails

MailVault is a free, open-source desktop app for macOS and Linux that connects to any IMAP email account and archives messages locally. Here is how the process works:

• Add your account — Enter your email credentials or sign in with OAuth2 (Google, Microsoft, Yahoo). MailVault connects via IMAP over TLS.
• Browse your mailbox — MailVault loads your email headers and displays your inbox. You can browse folders, search, and read emails just like any email client.
• Archive emails — Select the emails you want to keep and archive them. MailVault downloads the full message (headers, body, attachments) and saves it as an .eml file on your disk.
• Background caching — MailVault can also cache emails automatically in the background, downloading message content as you browse so your archive builds up over time without manual effort.
• Access offline — Archived emails are available immediately, even without an internet connection. Search, read, and export them anytime.

Benefits of Local Email Archiving

Once your emails are archived locally, you gain several advantages over keeping everything on the server:

• Offline access — Read and search your entire email history without an internet connection. Useful for travel, unreliable networks, or simply working faster.
• No vendor lock-in — Your emails are standard .eml files. Move them to any other email client, back them up to any storage, or write scripts to process them. You are not dependent on MailVault or any other software.
• Free up server storage — After archiving locally, you can delete emails from the server to reclaim space without losing anything.
• Compliance and retention — Keep emails for as long as you need them, regardless of provider policies. Back up your archive to multiple locations for redundancy.
• Speed — Reading emails from local disk is faster than fetching them from a remote server every time.
• Privacy — Your archived emails stay on your machine. They are not scanned, indexed, or used for advertising by any third party.

Who Needs Local Email Archiving?

Local archiving is valuable for anyone who takes their email history seriously. Freelancers and consultants who need to retain client communications. Small businesses that want a backup independent of their email provider. Professionals in regulated industries (legal, healthcare, finance) who must retain correspondence. Anyone switching email providers who wants to keep a complete history. Or simply anyone who has been burned by losing access to an account before.

Get Started

MailVault is free and open source. It runs on macOS (Intel and Apple Silicon) and Linux (x86_64 and aarch64). Download it, add your IMAP account, and start archiving your emails locally in minutes.

Have questions? Check the FAQ or see all features. Worried about losing emails when you delete from the server? Read our guide on keeping emails after server deletion.