Open an .olm file on Windows

Why Windows won’t open it

An .olm file is an archive made by Outlook for Mac: every message from the folders you exported, their attachments, and usually your contacts and calendar too. Inside, it’s a ZIP file full of XML, one file per message, in a layout only Outlook for Mac reads back. Outlook for Windows has no import for it, and double-clicking it on a PC either does nothing or offers to unzip a maze of folders.

That leaves a lot of people stuck: you’ve moved from a Mac to a PC, left a job and kept an export, or been sent someone’s mailbox to look through.

Open it here

1. Copy the .olm file to the PC (a USB stick, OneDrive or a network share all work; let a cloud copy finish downloading first).
2. Drag it onto this page, or press Choose a file and pick it.
3. The archive’s folders and messages are listed. Click a message to read it, with its pictures and attachments.

The archive is read in your browser on your PC, a piece at a time, so even an archive of several gigabytes opens without being loaded all at once. It isn’t uploaded anywhere. The first 10 messages are free to read; browsing every folder, searching and exporting are part of the £6 unlock.

Getting the mail into a Windows program

Reading is often enough. If you want the messages in a mail program, the unlock exports the whole archive as .mbox files (one per folder), as .eml files in folders, or as PDFs. Thunderbird, Apple Mail and most mail programs import .mbox. Outlook for Windows doesn’t import .mbox or folders of .eml directly; the honest routes into Outlook for Windows explains the ways that do work.

Contacts and calendar

When the archive includes them, contacts are exported as vCard files and as a CSV laid out the way Outlook for Windows imports contacts, and calendar events as an .ics file that Outlook, Google Calendar and Apple Calendar can import.

If it won’t open

• “Cut short”: the end of an .olm holds its list of contents, so a copy that stopped early can’t be read. Copy it again and compare the size with the original.
• “Holds an Outlook for Mac archive”: it was zipped again for sending. Unzip it first, then open the .olm inside.
• Password: Outlook for Mac doesn’t encrypt .olm files, so a password means someone zipped it with one. You need that password.