Open a .pst or .mbox file

What these files are

A .pst file is an Outlook data file: folders, emails, attachments, calendar items and contacts, all in one file. People end up with one from an old computer, from Outlook’s Export option, or when a colleague leaves and their mailbox is handed over. An .mbox file is the other common way to keep a whole mailbox: you get one when you export Gmail with Google Takeout, export a mailbox from Apple Mail, or copy a folder out of Thunderbird.

Open one here

1. Drop the .pst or .mbox file on this page, or press Choose a file.
2. The page lists the messages with their sender, subject, date and, for a .pst, the folder they’re in.
3. Click a message to read it and save its attachments. Attached emails open too.

The first 10 messages can be read for free. Browsing every message, and searching by subject, sender, recipient or folder, is part of the one-time unlock, which can also turn a whole mailbox into a ZIP of PDFs and attachments.

Size limits

Everything happens in your browser, so the file has to fit in your device’s memory. A .pst can be up to 150 MB and an .mbox up to 250 MB. A computer copes with big files much better than a phone. Larger .pst files need Outlook itself or a desktop program; in Outlook on Windows, use File, Open & Export, Open Outlook Data File. A Google Takeout of many years can be several gigabytes, but Takeout lets you export single labels, which gives smaller files.

.ost files

An .ost file is Outlook’s offline copy of a mailbox that lives on a server. Many open here the same way as a .pst. Some are tied to the Outlook profile that made them and can’t be read anywhere else; the page says so when that happens. Because the mail is still on the server, signing in to the mailbox is usually the easier route.

Apple Mail and Thunderbird exports

Apple Mail exports a mailbox as a folder whose name ends in .mbox, with the messages in a file called mbox inside. If Finder shows it as a single item, right-click it, choose Show Package Contents, and open the file named mbox here. Thunderbird’s folder files have no extension: a file called Inbox (next to Inbox.msf) is the mailbox. Open the one without .msf.

Password-protected .pst files

Outlook can put a password on a .pst file. Files with Outlook’s strong encryption can’t be opened here, and the page tells you. Getting around a password is not something this page does.

Private

A mailbox is about as personal as files get. This page never uploads it: the messages are read on your device, and nothing is kept after you close the tab.