Open a PST file without Outlook

What a .pst file is

A .pst is where Outlook keeps email on your computer: an archive you exported, the file Outlook calls Personal Folders, or an old mailbox from a job. An .ost is the copy Outlook keeps of a Microsoft 365, Exchange or Outlook.com mailbox. Both are Outlook’s own database format, and nothing but Outlook opens them. Without Outlook, on a Mac, a Chromebook or a phone, the usual advice is to buy a converter.

How it is read

• In this tab, from the file itself. CABINET reads Outlook’s format as Microsoft documents it: the indexes, then only the parts of the file each folder and message needs, when it needs them, so a large file is never uploaded or held in memory.
• Every folder, as Outlook shows it. The folders of the mailbox come first; Outlook’s own housekeeping folders are folded into one group below them. Unread, flagged and important email is marked, and an email attached to an email opens in place.
• Search. Search finds an email by who it is from and to and its subject, in one folder or in every folder; tick “Search the text of each email too” and it reads each email’s text as well, showing the words it found. Put a phrase in quotes to find it as a phrase. On a keyboard, / goes to the search, j and k open the next and the previous email, and Escape goes back to the list.
• Contacts and calendars. A contact saves as a vCard (.vcf) and a calendar or a task list as iCalendar (.ics), which phones, Apple’s Contacts and Calendar, Google and Outlook all import. A repeating meeting stays one meeting that repeats, in the time zone it was made in, so it keeps its time when the clocks change. Add to Contacts and Add to Calendar take them into the Workspace’s own Contacts and Calendar, in a new tab, without a file in between.
• Into formats everything reads. Any email saves as an .eml, which Apple Mail, Thunderbird, Outlook and Gmail’s importers open. A folder, or every email in the file, saves as one .mbox, which Thunderbird and Apple Mail import and POSTBAG opens. The whole file can also save as one .zip that keeps its folders: each folder as an .mbox, or each email as an .eml, with the contacts and calendars beside them.
• Nothing in an email runs or reports back. HTML email is shown in a sealed frame: scripts and forms are taken out, links do nothing, and pictures that live on the internet are not loaded, since loading one tells the sender the email was opened. Printing uses a frame sealed the same way.

What it does not read

Two kinds of .pst are recognised and named rather than guessed at: files in the Outlook 97 to 2002 format, from before Outlook used Unicode, and files made with Outlook’s “high encryption” setting. Outlook 2003 or later can open either and save a copy in the current format. A password set on a .pst is not encryption and is not needed here. When a single occurrence of a repeating meeting was moved, it is kept at its usual time; one that was deleted is left out. Outlook’s autocomplete list (the Recipient Cache) is not written into a whole-file .zip, because it is not contacts anybody saved.