Folders and labels
All messages
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Select a message from the list to read it here.
Univik Online MBOX Viewer
100% private. Runs only on your device
ChromeOS has no mail program that reads a mailbox file. This page does, straight from Files or Google Drive, with nothing installed and nothing sent off the device.
Or pick it from your device. Messages open in this tab, on your own computer, phone or tablet. Your mailbox is never uploaded.
A Chromebook is built around Gmail, and Gmail cannot import a mailbox file, not even the one Takeout wrote. There is no Thunderbird for ChromeOS and the Android viewers do not always run on managed devices. This page makes Chrome itself the reader, from the Files app, with nothing installed and nothing uploaded.
No Android app from the Play Store and no Linux container to set up. The browser every Chromebook already has is the whole tool, nothing added.
Downloads, My files, Google Drive and the Linux files folder all show in the picker, so wherever the mailbox landed, it is one click away.
A school or work device that blocks installs still lets a web page run. Nothing is installed, so nothing is blocked.
Attachments and .eml copies of messages go to Downloads, where Drive, Gmail or any app can pick them up.
Short answer: anything running ChromeOS, Chrome OS as it was once spelled, with a current Chrome. A cheap school Chromebook, a Pixelbook, a ChromeOS tablet or an old laptop revived with ChromeOS Flex all behave the same.
The full three pane layout, labels on the left, list in the middle, message on the right, the same as any laptop.
Detach the keyboard and the page switches to the touch layout with a Folders button. Reattach it and the panes come back.
An old Windows laptop or Mac running ChromeOS Flex has the same Files app and the same Chrome, so an mbox archive from its previous life opens right here.
Enrolled Chromebooks often block the Play Store and the Linux container. A web page is usually allowed, which is the point of this one.
Load the page while online, then open the mailbox with Wi-Fi off. Reading continues, which shows the file is not going anywhere.
Chrome on ChromeOS runs the same parser as Chrome anywhere else, so a Chromebook gets the complete tool.
Chromebook users are Gmail users, so the mailbox is usually a Takeout export. Every label shows on the left with a count, and the tool reads the big file in pieces.
A mailbox sitting in Drive shows in the Files app picker. Mark it Available offline in Drive beforehand, so the entire file sits on the device by the time Chrome asks for it.
If you run mutt or Thunderbird in the Linux container, its files appear under Linux files in the picker. The tool opens them here without leaving ChromeOS.
A PDF or image inside a message shows on its own tab and one click sends it to Downloads, in reach of Files, Drive and every Chrome app.
The Headers tab keeps Message-ID, Received and DKIM exactly as written, for checking where a message came from.
A Thunderbird Inbox brought over from a PC has no .mbox ending. The Files app shows it as a plain file and the tool opens it all the same.
Download it in Chrome or drop it into Google Drive from another computer. A Takeout archive unzips in the Files app. It shows up under Downloads, My files or Google Drive.
Click Choose .mbox from Files. The Files app opens as the picker; find the mailbox and pick it. The list fills while Chrome reads the file locally.
Open a message to read it. The Attachments tab saves any file to Downloads, and a message itself saves as .eml for another program.
The Files app is the only door, and these are the ways a mailbox gets behind it.
Request the export in Chrome and download the zip. Double click it in the Files app and it mounts like a drive; copy the .mbox out of Takeout, then Mail, into Downloads. Details on the Gmail Takeout viewer page.
Drop the file into Drive from any other computer and it appears in the Files app under Google Drive. Right click it and choose Available offline before opening it here.
Plug it in and the Files app lists it on the left. Pick the mailbox from there directly, or copy it to Downloads first for a large file.
Mail from mutt, Thunderbird or a copied /var/mail spool inside the container shows under Linux files. The Linux mailbox page covers those formats.
On ChromeOS this tool is the only practical viewer, and it handles most archives. For a huge export, search inside every message body or printing, the free Univik MBOX Viewer for Windows on a PC is the heavier tool.
| Feature | Online viewer on Chromebook | MBOX Viewer for Windows |
|---|---|---|
| Install needed | None, opens in Chrome | 15 MB Windows setup |
| Device | Any Chromebook or ChromeOS Flex | Windows 7 to 11 |
| Files uploaded | Never, read from the Files app | Never, runs on your PC |
| Managed devices | Runs where installs are blocked | Needs install rights |
| Search | Sender, subject, recipients, labels | Message bodies too |
| Large exports | Read in pieces, multi GB files open | No size limit |
| Chrome print | Direct printing | |
| Price | Free | Free |
Not with anything built in, since ChromeOS ships no mail client and Gmail does not import mailbox files. It can with this page. Pick the .mbox from the Files app and the tool reads it in Chrome, attachments and all, with nothing installed.
Gmail exports to mbox but has never imported one, on any device. The file Google gave you is for other programs, and on a Chromebook those do not exist. Unzip the archive in Files, then open the .mbox here.
No. Both are routes to a viewer, and both are often switched off on school and work Chromebooks. This page needs neither. If you already have the Linux container running, its mail files open here too.
Yes, through the Files app, which shows Drive as a folder. Right click the mailbox there and choose Available offline, which pulls the complete file onto the Chromebook before Chrome opens it. A file still in the cloud reads slowly or stalls.
No. Chrome reads the file from the Files app and sends nothing out. Load the page, turn Wi-Fi off and open the mailbox. It works the same, which matters on a shared or managed device.
Usually, yes. Admins block the Play Store and the Linux container far more often than they block ordinary websites, and this is an ordinary website that installs nothing. If a filter blocks the page itself, that is a policy question for the admin.
Double click the zip in the Files app and ChromeOS mounts it as a folder on the left. Open Takeout and then Mail, then drag the .mbox into Downloads. Eject the zip afterwards. Then pick the mailbox from Downloads on this page.
Yes. Open the message, click the file in the Attachments tab and Chrome saves it to Downloads. From the Files app you can then move it to Drive or open it in any app. A message saves the same way as .eml.
No Android app, no Linux container required. Chrome itself reads the mailbox from the Files app and nothing leaves the device.
Pick an .mbox on this Chromebook