How to open a .pst file without Outlook

Updated November 2026

Short answer: a .pst file is a normal file on your disk, and other programs can read it. Free tools such as XstReader open it one message at a time; PST Rescue opens it, searches it and exports it to PDF, .eml or .mbox on Windows. None of them need Outlook or a Microsoft 365 subscription.

Why your .pst file stopped opening

A .pst (Outlook Data File) is where classic Outlook keeps archived and exported mail. A .ost is the offline copy Outlook keeps for an Exchange or Outlook.com account. Three things commonly leave people with a file they can't open:

New Outlook. It opens .pst files only with classic Outlook also installed, a Microsoft 365 subscription, and matching 32/64-bit versions, and not on ARM PCs (Microsoft Support). See what new Outlook supports.
Office Home 2024 doesn't include classic Outlook. One buyer was told "Outlook data files require a Microsoft 365 subscription" (Microsoft Q&A).
A new mail app. Thunderbird's Outlook import reads mail through Outlook itself, so it needs Outlook installed (Mozilla Bugzilla 297533).

Option 1: Classic Outlook, if you still have it

File > Open & Export > Open Outlook Data File. This is the easiest route if a PC with classic Outlook is still around. Copy the .pst to that PC, open it, and export what you need.

Option 2: XstReader (free, open source)

A free viewer for .pst and .ost files on Windows (GitHub).
Good for: reading messages and saving them as HTML, RTF, text or .msg.
Watch out for: no PDF or .mbox export, and a technical interface. It's a zip download, not a Store app.

Option 3: readpst (free, command line)

The libpst project's readpst converts a .pst into mbox or .eml files (five-ten-sg.com/libpst). It is built for Linux; on Windows you'd run it in WSL. Good for technical users; no way to look at mail first.

Option 4: Trial versions of paid viewers

Many Windows PST viewers let you read for free but limit exports to 10 to 25 items per folder, or hide attachments, until you buy a licence, often a yearly one (LazyAdmin's comparison). Check the limits and the renewal terms before paying.

Option 5: PST Rescue (Windows, everything stays on your PC)

Open: ANSI and Unicode .pst, Outlook 2013 and later .ost, and password-protected .pst files.
Read and search, free: the whole folder tree, HTML mail and attachments, with search across subject, people and body.
Save, free: any single message as PDF or .eml, any attachment.
Export everything: folders or the whole file to .eml, .mbox, PDF and attachment folders, keeping your folders. First 50 messages free, then $29 once.

It reads healthy files. It does not repair corrupt .pst files.

Get PST Rescue from Microsoft Windows 10 and 11

Avoid uploading your mail

Online "PST viewer" sites ask you to upload the whole file. A .pst usually holds years of private mail, contacts and attachments. Downloaded viewers from unknown sites carry their own risks (GoldFynch). Prefer tools from a known source that run on your own PC.

Which one should you use?

You still have classic Outlook somewhere: use it.
A few messages, and you're comfortable with technical tools: XstReader.
You want to read, search, and get the mail out as PDF, .eml or .mbox: PST Rescue.

Questions

Can I open a .pst file in new Outlook?

Only with classic Outlook also installed and a Microsoft 365 subscription, per Microsoft's support page. Without those, new Outlook can't read it.

What's the difference between .pst and .ost?

A .pst is an archive you or Outlook created. A .ost is Outlook's offline copy of a server mailbox. Both store mail the same way, and PST Rescue opens both.

My .pst has a password. Can I still open it?

Yes. Outlook's .pst password doesn't encrypt the mail, so PST Rescue opens the file without asking for it.

Can I open a .pst file on a Mac?

Apple Mail can't open .pst files. Convert the file to .mbox on a Windows PC, then use File > Import Mailboxes in Apple Mail.

More: Move a .pst into Thunderbird with .mbox · What new Outlook supports for .pst files