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Univik Online MBOX Viewer
100% private. Runs only on your device
Read the mbox from a Vault matter, Gmail, Google Groups or Google Chat, without Thunderbird, Outlook or a litigation platform. Read only, on your own machine, nothing uploaded.
Or pick it from your device. Messages open in this tab, on your own computer, phone or tablet. Your mailbox is never uploaded.
A Vault export is evidence, or close to it, whether the job is eDiscovery, compliance or a forensic first review. This page opens the mbox from a matter in your browser, reads it where it sits and never writes to it. There is no upload, no account and no mail client between you and the messages.
The tool opens the file for reading and nothing else. It makes no copy and leaves no trace on the export, which matters for chain of custody once a hash has been recorded.
Message-ID, Received, Date, DKIM-Signature and every other header appear unchanged in the Headers tab, so a reviewer can check routing and timing without a second tool.
Google's own review advice is Thunderbird for mbox or Outlook for PST. Neither needs to be installed on the review machine when the file opens here.
Save one message as .eml with its headers intact, download an attachment or export the list as .csv for a quick index of what the export holds.
Short answer: extract the export zip on the machine you review on, then load the .mbox on this page. It works in the browser on a Windows workstation, a Mac, a Linux box, a Chromebook or a tablet.
Extract the zip, open this page in Edge or Chrome and pick the mbox. No Outlook licence and no PST conversion needed for a first look.
Double click the zip to extract it and open the mbox here in Safari or Chrome. Nothing gets imported into the Mail app.
Unzip from the shell or a file manager and read the mbox in Firefox or Chromium. Handy on a hardened review box with no mail client installed.
Unzip with the Files app or a file manager and open the mbox in the browser. Useful for reading a small matter away from the desk. Keep large exports on a computer.
A Chromebook has no mail client for mbox at all. Extract the zip in Files and read the mailbox here, in Chrome, without a client.
Vault writes message content and message metadata as separate things. The tool reads the content. The metadata files stay beside it for the record.
Gmail, Google Groups and Google Chat matters can all be exported as mbox. Each message in the file is shown with sender, recipients, date, subject and body.
Vault does not turn Gmail labels into folders. The labels for each message are recorded in the metadata CSV and XML that ship with the export, so keep those files with the mbox.
A big export arrives as several zip files and several mbox files. Each one is streamed in chunks, so a mailbox of several gigabytes opens without the browser holding it all in memory.
Point Select a folder at the extracted export and every mbox inside loads, with a switcher in the top bar. The CSV, XML and count files are skipped on their own.
Attachments open from their own tab and can be saved one at a time or zipped. HTML messages render with inline pictures, and remote images stay blocked so nothing phones home during review.
If the export excluded confidential mode content, those messages carry metadata only. The tool shows exactly what Vault wrote and nothing it did not.
In Google Vault open the matter, run the search and click Export. Choose mbox as the message format. When it is ready, download the zip from the Exports tab within 15 days.
Extract the zip. Drag the .mbox file into the upload box, or use Select a folder on the extracted folder to load every mbox at once. Leave the CSV and XML files where they are.
Open messages and check the Headers tab for Message-ID and Received lines. Save a message as .eml if a copy is needed. The source file is never written to.
Vault is the Google Workspace tool for retention, placing a legal hold and eDiscovery. An admin with the Manage Matters, Manage Searches and Manage Exports privileges can search a matter and export the results.
PST or mbox, chosen at export time for Gmail, Groups and Chat. Pick mbox to open the messages here. PST needs Outlook or a litigation platform.
A CSV and an XML file list the metadata Google recorded for each message, labels included. They are the record that links the messages to what sits on Google's servers.
export_name-result-counts.csv lists each searched account and how many messages were exported for it, with a Totals row first. If anything failed, Vault adds an error report naming the items.
Include or exclude confidential mode content, export linked Drive files and choose a data region if a policy applies. Expect multi party approval if an admin turned it on. Up to 20 exports can run at once.
A single Gmail user can export their own mailbox with Google Takeout, which writes mbox only. Those files open on the Gmail Takeout viewer page and carry labels inside each message.
This online page is for a first look at a Vault mbox on whatever machine is in front of you. For casework with hashing, reports, search inside message bodies and bulk export, use the free Univik MBOX Viewer for Windows.
| Feature | Online Vault 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 |
| Vault export folder | Every mbox in one folder | Whole export tree at once |
| Search | Sender, subject, recipients | Message bodies too |
| Large exports | Read in pieces, multi GB files open | No size limit |
| Browser print of the open message | Direct printing | |
| Price | Free | Free |
Yes. Google's help page suggests Thunderbird, a text editor or a litigation support system for mbox. This page is a fourth option: extract the export, drop the mbox here and read it, with no client installed and the file left untouched.
No. The browser opens the file for reading only and the tool never writes back to it, so any hash you recorded for the export stays valid. Nothing is uploaded and no working copy is made. If you need hashing done for you, that is a job for the Windows viewer.
In the metadata CSV and XML that Vault writes beside the mbox, not as folders. Google does not convert labels into mailbox folders. Open the CSV in a spreadsheet next to this viewer when you need a label for a given message.
It lists every account the search covered and the number of messages exported for each, with a Totals row at the top showing exported and error counts for the whole export. Compare it with the message count this viewer shows to confirm nothing was lost in extraction.
Yes, as long as mbox was chosen at export time. Vault offers PST or mbox for Gmail, Groups and Chat alike. A Chat export shows each conversation as a message, with the Chat labels recorded in the metadata file.
Treat it as a first look and a spot check. Early case assessment, confirming the right custodian was collected, checking a header or two. Production, Bates numbering, redaction and privilege review belong in a platform such as Relativity, and bulk export with reports belongs in the Windows viewer.
No. The whole viewer is this page. The file is read by your browser from local disk and no byte of it is sent out. The page keeps working offline with the network cable pulled, which is the easiest way to prove it to yourself.
Fifteen days from completion, from the Exports tab in the matter. Download it and store it with its metadata files inside that window. After that the export must be run again from the saved search.
Open the mbox from a matter with no mail client and without altering a byte. The export never leaves the machine you review it on.
Choose a Vault .mbox file