Arca Mail Backup vs. Mail Backup X: an honest comparison

Mail Backup X is a good pick if you want one app that gathers mail from your IMAP accounts and from Apple Mail, Outlook or Thunderbird, with backups to Google Drive, Dropbox, or a USB drive that syncs as soon as you plug it in. Arca Mail Backup is the better fit if you want your backup to be standard mbox files you can open without the app, on your own disk, a NAS or S3-compatible storage, and to be able to put mail back into your account when you need it. Both run on Mac and Windows, and neither keeps your messages on the vendor’s servers.

Facts checked in October 2026 against Mail Backup X’s official website.

What Mail Backup X is

Mail Backup X is made by inventPure Software, based in Toronto, Canada. It’s one of the few email backup tools that works the same on Mac and Windows, and it has been around for years: its change log lists version 2.0.26130 from May 12, 2026, and the one before it, 2.0.25232, from August 2025.

Here’s what its Personal Edition page says:

• It backs up IMAP accounts (Gmail, Outlook.com, iCloud, Yahoo, Zoho, GMX and others), Exchange servers, and mail stored in Apple Mail, Outlook, Thunderbird and Postbox.
• It backs up mail as it arrives, incrementally. Whatever you delete on the server stays in the backup.
• It stores highly compressed archives (“up to 3X storage space” saved) using its own algorithm, and you can encrypt them with a personal key. Lose that key, they warn, and not even they can recover the data.
• It saves to a local drive, Google Drive, OneDrive, Dropbox or FTP, and it can detect a USB drive when you plug it in and sync the backup to it.
• It has a built-in viewer to read and search backups, with filters for sender, dates and attachments, plus AND and OR operators.
• It imports and exports mbox, EML, PST, OLM and RGE.
• It mentions contacts and calendars, without details, and a native app for Synology NAS.

According to its store, the Personal edition costs $59 (shown marked down from $79), covers two computers and up to five mail profiles, and includes a year of updates. After that, updates are an optional $20 a year. Team editions start at $275 for five users.

Those are real strengths. It reads from more places than Arca does (Arca doesn’t read PST files or back up from desktop Outlook), cloud destinations like Drive and Dropbox are already there, and USB sync is handy if you keep your backup on a drive that isn’t always connected.

Where they differ

Backup format

This is the biggest difference. Mail Backup X stores mail in its own compressed archives, optionally encrypted with your key. Its website doesn’t document that format: you read your mail in its viewer, and to use it in another program you export it to mbox, EML or PST from the app. That works fine as long as you have the app installed and a version that runs on your system.

Arca writes standard mbox, one file per folder and month, along with a manifest.json, a copy of the SQLite index, and a README that explains how to open everything. Thunderbird, Apple Mail or MBox Viewer Pro open those files directly, with no export and no Arca needed. If you want to know why that matters so much, we cover it in What is an mbox file.

The trade-off is that Arca’s backup takes more space: mbox is plain text and attachments are stored in base64. That’s the price of being able to open your mail with any program ten years from now.

Destinations

Mail Backup X saves to a local drive, a USB drive, Google Drive, OneDrive, Dropbox or an FTP server. On the free plan Arca saves to an internal or external drive, and with Pro also to a NAS or S3-compatible storage (Wasabi, Backblaze B2, Cloudflare R2, Hetzner), to several destinations at once. With an S3 bucket that has object lock turned on, the backup stays safe even from ransomware that reaches your computer. For Drive or Dropbox, Arca Pro can use the folder those services sync on your computer.

Restoring

Mail Backup X’s website describes restoring as exporting your mail to the file format of your email app (PST for Outlook, mbox for Thunderbird or Apple Mail, and so on), which you then import yourself. Arca restores straight into the account: messages go back to the server, into a new folder, without touching anything already there, and by default only what was deleted comes back, so there are no duplicates. Mail imported from an .mbox file (a Google Takeout, for example) can be restored into another connected account.

How it connects to your accounts

Both use IMAP. Arca uses Microsoft’s official sign-in for Outlook.com and Microsoft 365, and keeps passwords in the macOS Keychain or Windows Credential Manager. Mail Backup X can also back up from desktop email apps, which helps if you have old mail that’s no longer on any server.

Price and license

Mail Backup X is a one-time purchase ($59 for two computers), and updates after the first year are optional. Arca is free for one account backed up to a disk on your computer; Pro starts at €9.99 a year for one account, or €49.99 for life for one account. Arca purchases go through each platform’s store (Mac App Store and Microsoft Store), so a purchase on your Mac doesn’t carry over to Windows.

Summary table

	Mail Backup X	Arca Mail Backup
Price	$59 (2 computers, 5 profiles); updates $20/year from year 2	Free for 1 account; Pro yearly from €9.99/year or lifetime €49.99 (1 account)
Platforms	macOS and Windows	macOS 14+ and Windows 10 (1809+) and 11
Sources	IMAP, Exchange, Apple Mail, Outlook, Thunderbird, Postbox	IMAP: Gmail and Workspace, Outlook.com and Microsoft 365, any hosting; import .mbox (Takeout, Apple Mail, Thunderbird)
Automatic backups	Yes, as mail arrives	Yes, in the background (daily free, every few hours with Pro)
Format	Its own compressed archive, optionally encrypted; exports to mbox, EML, PST…	Standard mbox per folder and month + manifest.json + README
Destinations	Disk, USB (syncs on plug-in), Google Drive, OneDrive, Dropbox, FTP	Internal or external drive; with Pro, NAS, S3-compatible and synced folders
Search	Built-in viewer with AND/OR and attachment filter	By subject, sender, recipient and text, with account, folder and date filters
Restore	Export to your email app’s format	Straight into the account, only deleted mail by default

Which one to choose

Stick with Mail Backup X if you have mail in desktop Outlook, Apple Mail or PST files that you want in the same backup, if your destination is Google Drive, Dropbox or FTP, or if you’d rather pay once and forget about it. It’s also the one for you if you want your USB drive to catch up on its own every time you plug it in.

Choose Arca if what matters most is a backup any program can open without depending on anyone, if you want to keep it on a NAS or in an S3 bucket (with object lock if ransomware worries you), or if you want putting mail back into your account to take a couple of clicks. And you don’t have to pay anything to start with one account.

How to try it

Arca Mail Backup connects to your accounts over IMAP from your own computer, with no servers of ours in between. It doesn’t back up calendars or contacts, only email. Whatever gets deleted on the server stays in your backup, marked as deleted, and you can find it and put it back.

It’s on the Mac App Store and the Microsoft Store, free for one account. Arca Pro plans are on the pricing page.