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Univik Online MBOX Viewer
100% private. Runs only on your device
The .mbox package that Mail writes when you export a mailbox, opened on a Mac or a Windows PC with no import. Nothing installed, nothing sent out.
Or pick it from your device. Messages open in this tab, on your own computer, phone or tablet. Your mailbox is never uploaded.
When you export a mailbox from the Mail app on macOS, you get a .mbox package. This page opens that package in your browser and reads the mailbox inside it where it already sits. No import back into Mail, no server and nothing sent anywhere.
Pick the .mbox package with the folder button. The tool looks past the index files and reads the mbox file that Mail put inside.
Move the export to Windows and the package shows up as a plain folder. Open it here in Edge or Chrome, no Mac needed.
Reading an old export usually means File, Import Mailboxes and a long wait. Skip that. The tool reads the file without touching your Mail library.
Save one message as .eml, download an attachment or zip every attachment of a message. Export the list as .csv for a record.
Short answer: copy the .mbox package to whichever machine you are on, open this page and use Select a folder. It runs in Safari, Chrome, Edge or Firefox on a Mac, a Windows PC, Linux, an iPad or a phone.
Open this page in Safari or Chrome on macOS Sequoia, Sonoma, Ventura or an older release, click Select a folder and pick the package. Handy for a quick look at an archive you do not want back in Mail.
Windows treats the .mbox package as a folder. Either pick that folder with Select a folder, or open it in File Explorer and choose the file named mbox with no extension.
The package is a normal directory on Linux too. Pick it in Firefox or Chromium and read the mail without any client set up.
AirDrop the package to the Files app, then open this page in Safari, tap Select a folder and pick it. The wide iPad layout shows list and message side by side.
ChromeOS cannot open a Mail export by itself. Copy the package over with a drive or Google Drive and pick it here in Chrome.
Export Mailbox does not write a single file. It writes a package, a folder that macOS shows as one item. The tool understands that layout.
Inside Inbox.mbox sits a file called mbox with no extension. That is the mailbox. The tool opens it and skips table_of_contents and any Info.plist beside it.
Exported Inbox, Sent and a few project mailboxes into one folder? Pick that parent folder and every mailbox loads. Switch between them from the top bar.
PDF, Office, image and zip attachments open in their own tab. Pictures placed inside an HTML message show in the message view.
Message-ID, Received, Date and DKIM lines stay exactly as written in the Headers tab, handy when you need to check where a message came from.
Subjects and sender names in Japanese, Arabic, Hindi or any other script are decoded and shown as real text.
A mailbox with years of mail is read in pieces, so a multi gigabyte export opens without the browser holding the whole thing in memory.
In the Mail app select the mailbox, then choose Mailbox and Export Mailbox and pick a folder. Mail writes a package such as Inbox.mbox there.
Click Select a folder and choose that .mbox package. The tool finds the mbox file inside and skips the index files. On Windows, open the folder and pick the file named mbox instead.
Open a message to read it, then use the Attachments and Headers tabs. Save anything you need as .eml or a zip.
Two different things live on a Mac: the live mail store and the exports. Only the exports are mbox.
Mailbox, then Export Mailbox writes Name.mbox in the folder you choose. If a package with that name already exists, Mail does not overwrite it and writes Name 2.mbox beside it. In Finder, right click the package and choose Show Package Contents to see the mbox file inside.
Mail stores current mail under ~/Library/Mail/ in a folder named V plus a number, such as V10, that changes with each macOS release. Those are .emlx files with one message each and they are not mbox, and a Time Machine backup of that folder is the same. Export first, then open the export here.
Local mailboxes under On My Mac and mailboxes synced from iCloud or any IMAP account export the same way, including a Proton Mail account added through Bridge. Select the mailbox in the sidebar and use Export Mailbox.
To bring a mailbox back into Mail later, use File and Import Mailboxes. Choose Apple Mail for a Mail export. Choose Files in mbox format for a mailbox from Thunderbird, Gmail, a Windows program or an old Entourage export.
Two Univik options. The online page here is for reading one export wherever you are, Mac included. The free Univik MBOX Viewer for Windows takes a whole folder of Mail exports at once, searches inside message text and prints.
| Feature | Online Apple Mail Viewer | MBOX Viewer for Windows |
|---|---|---|
| Install needed | None, opens in the browser | 15 MB Windows setup |
| Operating system | Windows, Mac, Linux, Chromebook, iOS, Android | Windows 7 to 11 |
| Files uploaded | Never, runs on your device | Never, runs on your PC |
| .mbox packages | One folder of exports at a time | Any number of exports at once |
| Search | Sender, subject, recipients | Message bodies too |
| Large mailboxes | Read in pieces, multi GB files open | No size limit |
| Browser print of the open message | Direct printing | |
| Price | Free | Free |
Open this page, click Select a folder and choose the .mbox package. The tool reads the mailbox inside it and lists the messages. Nothing is imported and your Mail library is not touched. This is the quick way to check an old archive you kept on a drive.
Because it is one. macOS shows a package as a single item, but underneath it is a folder holding a file named mbox and a table_of_contents index. Windows has no idea about packages, so it shows the folder as it really is. Pick the folder here, or open it and choose the mbox file.
The one called mbox, with no extension at all. It holds every message. The table_of_contents file next to it is an index Mail keeps for itself and holds no mail. If you pick the whole package with Select a folder, the tool sorts this out for you.
Yes. Carry the .mbox package over on a USB stick or through a shared folder and load this page in Edge or Chrome. No conversion to PST and no Outlook involved. If you want a full folder of exports at once, the Windows viewer linked above does that.
No. The live store under Library, Mail, V10 or another V number holds one .emlx file per message, and that is a different format. Select the mailbox in Mail and use Export Mailbox first. The .mbox package it writes is what opens here.
No. The mailbox is read by your own browser from the package on your disk. There is no server, no account and no copy made anywhere. Go offline after the page loads and it keeps working.
Yes. Export them all into one folder in Mail, then pick that parent folder here with Select a folder. Every package inside is loaded and a drop down in the top bar lets you jump between mailboxes.
Thunderbird can import the mbox file inside the package directly. For Outlook, or for a handful of messages anywhere, open the export here and save the ones you want as .eml. An .eml opens in Outlook, Thunderbird and Mail alike, with attachments and headers intact.
Point the tool at the .mbox package and the messages appear, with no import into Mail. Everything stays on your Mac or PC.
Choose an Apple Mail export