What's new in Mbox Viewer

The search field no longer disappears while you type

• Fixed The search field no longer vanishes from the toolbar while you type. At certain window widths, entering a query could push it out of view with no way to bring it back until you resized the window. It now keeps a fixed width; the match count is still shown in the status bar.
• Fixed ⌘F now always leads somewhere: if the search field can't be focused, it opens the Search Filters panel instead of doing nothing.

Export to PDF and HTML, repair damaged mailboxes, and new inspection views

• New Export any message to PDF. The exported PDF keeps the same layout as printing, in a self-contained multi-page file. Exporting one message is free; batch PDF export (several at once) is a Pro feature.
• New Export any message to a self-contained HTML file — headers, body with inline images embedded, and attachments included as downloadable links — so it opens anywhere with no external references. Single-message export is free; batch export is Pro.
• New New attachments pane: a gallery that lists every attachment with a per-type icon, its content type and size, image preview and one-click save — including “Save all” to a folder.
• New Three new ways to inspect a message, alongside Text and Headers: a Properties view (all addresses, dates and threading identifiers, selectable and copyable), a MIME structure view (the message's part tree with content types, encoding, charset and sizes) and a Hex view (an offset · hex · ASCII dump of the raw message) — ideal for technical or forensic inspection.
• New Repair damaged mailboxes (Pro). When a mailbox opens empty or as one giant message, its “From ” separators were probably lost; a deep-scan recovery re-detects the message boundaries. You can rebuild the view in place or export a brand-new, repaired .mbox copy — and the original file is never modified (the app stays strictly read-only).
• Improved Merge mailboxes with full traceability: a new option adds an “X-Mbox-Source” header to each merged message with its origin file name, so a combined archive still shows which mailbox every email came from. Off by default, and it works with or without duplicate removal.

Merge Mailboxes fixes and a 1 GB free limit

• Fixed The “Merge Mailboxes” picker no longer greys out your mailboxes: you can now select any recognizable mailbox — including extensionless Thunderbird mailboxes (INBOX, Sent…), .mbs/.mbx archives, files on a NAS, and Apple Mail “Name.mbox” export folders.
• New Merging up to 1 GB of combined mailboxes is free; larger merges are now a Pro feature, shown with a clear notice and an upgrade option.

Faster, more private, more accessible

• Improved Faster on large mailboxes: quicker searching, lower memory use, and no more UI freezes when opening very large messages or exporting.
• Security More private: remote images (tracking pixels) are blocked more thoroughly, temporary files are cleaned up automatically, and new Settings let you clear your search history and index cache.
• Improved More accessible: full VoiceOver and keyboard support, adjustable message text size and font, better contrast, and the in-app language picker now lists all 18 languages.
• Fixed More robust: handles malformed or oversized MBOX/EML files gracefully instead of freezing or crashing, and export/merge failures are now clearly reported.
• New HTML messages now show the sender header and quick actions (Export, Print, Share) at the top, just like plain-text messages.

Full Headers view and 8 new languages

• New New Full Headers view: see the complete header block (From, To, Cc, Date, Message-ID, Reply-To and more) in a clean, read-only pane. Pick it from the toolbar (Text / Headers / Raw) or from View → Full Headers (⌘2). Thanks to Verender Badial for the suggestion.
• New Eight new languages — Simplified Chinese, Traditional Chinese, Turkish, Swedish, Danish, Norwegian, Russian and European Portuguese — bringing the app to 18 languages.

Apple Mail and Thunderbird exports open directly

• New Apple Mail export folders (.mbox packages) now open directly — no need to dig out the inner “mbox” file.
• New Mailbox files without an extension — like Thunderbird's INBOX or Sent — open directly, no renaming to .mbox required.

Safer HTML and smarter search

• Security Email HTML is now sanitized before display — scripts, iframes and other active content are stripped, on top of the existing remote-image blocking.
• Improved Free-text search now looks inside message bodies too, not just subject and sender — so a plain word finds everything.
• Fixed Hardened parsing of very large files so a message split across read buffers can never inflate the message count.

Accurate version info and code redemption

• Fixed The About window now always shows the real installed version.
• New Added a «Redeem Code» button so you can use Mac App Store promo codes for the Pro upgrade.

Pro is now a simple one-time purchase

• Improved Streamlined the App Store edition to a single lifetime Pro unlock. The upgrade screen now loads its price instantly.

Clearer upgrade path

• New Added an «Upgrade to Pro» banner on the welcome screen so unlocking unlimited file size is one tap away.
• Fixed Several refinements to the purchase and restore flow.

New Window shortcut and legal links

• New Added a New Window command (Cmd+N) and quick links to the Privacy Policy and Terms.
• Improved Clicking the Dock icon with no windows open now reopens the welcome window.

Mbox Viewer arrives on the Mac App Store

• New First Mac App Store release, with sandboxing and automatic updates through the App Store.
• Fixed Resolved several export and save-panel issues for a smoother experience.

Now speaking ten languages

• New Added German, French, Italian, Japanese, Korean, Dutch, Polish and Brazilian Portuguese — full UI and user guide.

Mbox Viewer 1.0 — the first release

• New Streaming MBOX and EML reader that opens files of any size without loading them into memory, with an instant-reopen binary index.
• New Powerful search syntax, Gmail labels, conversation threading, and export to EML, CSV, text and attachments.
• New Fully native macOS app — SwiftUI + AppKit, dark mode, Drag & Drop, Quick Look, Share and Print.

Export to PDF and HTML, repair damaged mailboxes, and new inspection views

• New Export any message to PDF. The exported PDF keeps the same layout as printing, in a self-contained multi-page file. Exporting one message is free; batch PDF export (several at once) is a Pro feature.
• New Export any message to a self-contained HTML file — headers, body with inline images embedded, and attachments included as downloadable links — so it opens anywhere with no external references. Single-message export is free; batch export is Pro.
• New New attachments pane: a gallery that lists every attachment with a per-type icon, its content type and size, image preview and one-click save — including “Save all” to a folder.
• New Three new ways to inspect a message, alongside Text and Headers: a Properties view (all addresses, dates and threading identifiers, selectable and copyable), a MIME structure view (the message's part tree with content types, encoding, charset and sizes) and a Hex view (an offset · hex · ASCII dump of the raw message) — ideal for technical or forensic inspection.
• New Repair damaged mailboxes (Pro). When a mailbox opens empty or as one giant message, its “From ” separators were probably lost; a deep-scan recovery re-detects the message boundaries. You can rebuild the view in place or export a brand-new, repaired .mbox copy — and the original file is never modified (the app stays strictly read-only).
• Improved Merge mailboxes with full traceability: a new option adds an “X-Mbox-Source” header to each merged message with its origin file name, so a combined archive still shows which mailbox every email came from. Off by default, and it works with or without duplicate removal.

Merge from settings, safer viewer and a more reliable engine

• New Combine mailboxes right from the settings (⚙) menu — including the mailbox you already have open. Merging up to 1 GB combined is free; Pro unlocks larger merges.
• Improved More reliable: merging never leaves a corrupted file, message dates display more accurately, and very large or damaged mailboxes are handled safely.
• Security Stronger security: the email viewer now blocks all remote and local-network content (tracking pixels and file/UNC links), preventing information leaks.

More formats, sort by recipient and safer HTML

• New Open more mailbox formats: Apple Mail, Thunderbird, and .mbs/.mbx files — plus a new “Open folder…” command and folder drag-and-drop.
• New New “Sort by recipient (To)” option in the message list.
• Security Stronger security: email HTML is now sanitized before it is displayed (scripts and remote content are blocked).
• Fixed Various improvements and fixes.

Mbox Viewer arrives on Windows

• New A native Windows app (WinUI) is coming to the Microsoft Store, built on the same streaming engine that opens MBOX and EML files of any size — up to 50 GB — without loading them into memory.
• New Feature parity with the Mac app: powerful search, Gmail labels, conversation threading, export to EML/CSV/text, 18 languages and the same Free / Pro one-time purchase.

Windows port begins in the lab

• New We start building the native Windows port: a WinUI 3 app (Windows App SDK) written in C# 12 / .NET 8, with WebView2 (Edge Chromium) rendering the email HTML in isolation.
• New It reuses the same streaming approach as the Mac app — opening huge MBOX/EML files without loading them into memory — and will ship as an MSIX package on the Microsoft Store, with the Pro unlock via Windows.Services.Store.