Archiving Your Email: How to Export a Mailbox for the Long Term

Most of us have thousands of emails going back years: receipts, contracts, travel plans, family messages and work records. They live on a provider's servers, and that is a risky place to leave the only copy. Accounts get closed, storage limits force deletions, and access can be lost. An email archive gives you a copy you control.

Why archive email at all

There are several good reasons. You might want to free up space in a mailbox that is nearly full, keep records of purchases and agreements, or move to a new provider and bring your history with you. Some people simply want a personal record that does not depend on any single company. Rules on how long businesses must keep correspondence differ by country and industry, so if the mail is for work, check what applies to you.

Know the common formats

Email programs store messages in a few common formats:

• MBOX. One large file holding many messages as plain text. It is an open format that many programs can read and import.
• EML. One file per message. It is easy to open, search and organize, though a large mailbox produces a very large number of files.
• PST. A format used by Microsoft Outlook. It is convenient if you stay in that ecosystem, but it is proprietary, and very large files can be unwieldy.
• Provider export bundles. Some webmail services let you download your data as a package, often in MBOX form.

For long-term safety, an open format such as MBOX or EML is the better choice, because many tools will still be able to read it in the future.

Step by step: exporting

1. Decide what to include. All folders, or only certain years or labels? Remember sent mail, drafts and any custom folders.
2. Use the official export option. Look in your email program or in your account's data download settings. Large mailboxes may take hours, and some services email you a link when the file is ready.
3. Download to a local drive, not to a temporary folder you will clean out later.
4. Keep the structure. If you can, export folders separately by year or topic so that you can find things later.

Check the result

An archive you cannot open is worthless, so test it:

• Compare the number of messages in the export with the number in the original folders.
• Import or open the archive in a second email program to see that it works.
• Open a few old messages, especially ones with attachments, and make sure the attachments are intact.
• Search for a known phrase to check that the text was saved properly.

This fits well with the habit described in our guide on testing your backups and restoring files.

Protect the archive

Email often contains personal and financial information, such as account numbers, addresses and sensitive conversations. Treat your archive accordingly:

• Store it in an encrypted container or encrypted archive with a strong, unique password.
• Keep at least two copies on separate devices or locations, in line with the 3-2-1 backup rule.
• Avoid leaving it in a general-purpose folder such as Downloads.
• Record the password in a safe place, because there is no way to recover an encrypted archive without it.

Organize and label

A short text file next to the archive makes a big difference later. Note the account name, the date range, the export date and the format. Use clear names, such as a year range and account label, following the ideas in our folder structure and naming guide.

Deleting from the server

Only delete messages from the provider after you have verified the export and made a second copy. Many people prefer to leave recent mail online and archive only older years.

Frequently asked questions

Can I search an archive later? Yes, if you import it into an email program, or for EML files, by using your computer's search. MBOX files can be opened by many programs.

How big will the archive be? That depends mostly on attachments. A mailbox with years of photos and documents may take many gigabytes.

Should I archive everything? Not necessarily. Many people discard newsletters and obvious junk first, which saves space and makes the archive easier to use.