How MailVault archives mail, what archiving then deleting does to the server copy, when automatic backups run, and how to export and re-import your vault.
MailVault connects to your email server (over IMAP, or Microsoft Graph for personal Outlook.com accounts) and downloads each email as a standard .eml file stored in Maildir format on your computer. Each email is one file on disk — human-readable, portable, and compatible with any mail client. Once a message is in your vault you can delete the server copy to free up space; the local one is unaffected.
Archiving downloads the full email from your server (if not already cached) and stores it as a .eml file on disk with the A (Archived) flag in the filename. If the email was already cached locally, MailVault simply renames the file to add the archive flag. Archived emails appear under the Vault view and are included in backups. The server copy is untouched until you delete it yourself.
Archive & Delete, a Premium feature, runs three steps in order: it copies the message into your vault as an .eml file, checks that the copy is really there, and only then deletes it from the server. Anything that fails the check stays on the server — a failed copy never costs you the original. Afterwards the row shows your only copy: the vault is the one place that message still exists, which is also the cue to keep a backup drive attached.
Archive, Back up & Delete, also Premium, adds a second copy: it copies each message to your backup folder as well, checks both copies, and removes from the server only what both confirm. It needs a backup folder chosen first. If the drive cannot be reached, or a copy does not match, nothing is deleted for those messages and the result tells you how many stayed on the server.
Two jobs in Settings → Backup & Restore → Archive & delete, both Premium, do the same for a whole account instead of selected messages. Archive, back up & delete from server saves the mail you scope to your vault and your backup folder, and Archive & delete from server saves it to your vault only. You choose the folders and the dates (all dates, this year, last year, older than 2 years, or the years you pick), whether to delete after everything is saved or as each email is saved, and whether to move to Trash or move to Trash and empty it, and a summary shows what will be removed before you confirm. Every copy is checked before an email is removed, the job keeps running in the background and after a restart, and it waits for your daily download limit or for Gmail’s own limits instead of failing.
Anything you archived first stays in your vault, untouched by what the server does afterwards — that is the whole point of the product. Anything you did not archive is gone with the server copy, so MailVault shows the state of every message on its own row before you delete: on the server, in your vault, or both. The safe route is Archive & Delete (Premium), which copies each message into your vault and verifies it there before removing it from the server.
MailVault exports your emails as a ZIP archive containing all .eml files plus a manifest.json that maps emails to accounts by email address (not internal IDs), making backups portable across different installations. You can choose to export all emails or archived only. Importing is idempotent — if an email already exists locally, it won't be duplicated. If a backup contains emails for an account you haven't set up yet, MailVault creates it automatically (you just re-enter the password in Settings).
Yes, with Premium. Settings → Backup & Restore → Backup Schedule offers four frequencies: every hour, once a day, once a week, and At set hours. Choose At set hours and a grid of all 24 hours appears; tap the ones you want, say 07, 12 and 22, and MailVault backs up on the hour at each of them and never in between. Every frequency runs only while the app is idle, so a backup never starts under your hands.
Set hours are meant for a vault or backup mirror on an external drive that something else already uses on its own schedule, Time Machine most often: pick the hours that drive is free. A selected hour that comes round while MailVault is busy is skipped rather than caught up later, so the next selected hour is the next attempt.
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