Is it safe to open confidential or legal PST files in OnlinePSTViewer.com?

Yes, 100%. OnlinePSTViewer.com operates on an air-gapped client-side model engineered by Prismmigration. When you select a file, the browser reads it directly into local memory using HTML5 File API and Web Workers. Zero file data, email content, or metadata is ever transmitted over the internet.

Can I open PST files on Mac, Linux, or Chromebook?

Yes! Because OnlinePSTViewer.com runs inside modern web browsers (Chrome, Edge, Safari, Firefox), you can open and read Outlook PST and OST files seamlessly on macOS, Linux, ChromeOS, iPad, and Windows without needing Microsoft Office or Outlook installed.

What is the difference between PST and OST files?

PST (Personal Storage Table) files are used by Microsoft Outlook for archiving and POP3 email accounts. OST (Offline Storage Table) files are cached local copies created by Exchange, Office 365, and IMAP accounts. OnlinePSTViewer.com parses both formats seamlessly.

Is there a file size limit for PST archives?

There are zero file size limits. OnlinePSTViewer.com utilizes client-side chunked byte slicing directly from your hard drive, meaning multi-gigabyte PST files of any size (50 GB, 100 GB+) open smoothly without overwhelming browser memory or uploading data to servers.

How can I open .msg files without Microsoft Outlook installed?

OmniPST MSG Viewer parses Microsoft Compound File Binary (CFB/OLE) formats directly in your web browser. You can open any Outlook .msg file on Mac, Windows, Linux, or mobile without paying for Microsoft 365.

Can I download attachments from MSG files?

Yes! All embedded attachments (PDFs, Word documents, Excel spreadsheets, images) are decoded and made available for instant 1-click download.

Is my MSG email uploaded to remote servers?

No. OmniPST parses your .msg file entirely inside your browser memory (RAM). Zero bytes are transmitted to any cloud server, ensuring 100% enterprise privacy and compliance.

100% Free • Private In-Browser Viewer

Free Online Outlook MSG Viewer

Open, view, and extract individual Microsoft Outlook .msg files directly in your web browser. View email bodies, sender metadata, and attachments without Outlook.

Drag & Drop your MSG file here

Supports all Microsoft Outlook MSG versions (.msg)

No data sent to server (100% RAM)Preserves authentic Outlook stylingWorks on Mac, iPhone, Android & PC

Engineered for High-Fidelity Outlook MSG Viewing

Open individual Outlook emails instantly on any device without Microsoft 365 or Outlook desktop software.

1. 100% Client-Side Privacy

Your MSG files are parsed locally in browser RAM. No email content or corporate attachment is ever transmitted to any cloud server.

2. Full Rich Text & HTML

Renders the authentic Microsoft Outlook email design, original typography, inline images, and recipient distribution lists.

3. Extract Attachments & PDF

Extract embedded documents and images with one click, or export the entire MSG message to universal PDF or EML format.

4. MAPI Properties & Headers

Inspect raw MAPI message descriptors, transport headers, transmission timestamps, and message class tags for forensic review.

5. Cross-Platform Mac & Linux

Open Windows Outlook MSG files on Apple macOS, Ubuntu Linux, ChromeOS, iPad, and iPhone without running Windows virtual machines.

6. Keyboard Shortcut Controls

Press 'f' to expand reading to full screen, 'p' to print/PDF, and '?' to display the full keyboard cheatsheet instantly.

Unrivaled Speed & Privacy

OmniPST vs Other MSG Viewers

Why users prefer OmniPST over paying for Microsoft Outlook or uploading sensitive corporate emails to cloud servers.

Feature & Security Capabilities	OmniPST MSGYou	Microsoft Outlook ($99/yr)	Cloud Uploaders
Zero Server Upload (100% In-Browser Privacy) Parsed in local browser memory. Zero network transmission.
Zero Software License or Subscription Cost Outlook requires Microsoft 365 license costing $69 to $99 per year.
Native Cross-Platform macOS & Linux Support Outlook for Mac often struggles to open legacy Windows Outlook .msg files.
1-Click PDF Printing & EML Export Export messages to vector PDF or open standard RFC 822 EML in 1 click.
Direct Attachment Extraction Preview and download embedded Word, Excel, PDF, and image files.
Forensic MAPI Transport Header Inspector Inspect low-level MAPI descriptors and transport routing headers.
Pricing & Account Barrier Open unlimited MSG files without entering email or credit cards.	100% Free & No Signup	$99/yr Office 365	Paid / File Size Capped

How to Open Outlook MSG Files Without Outlook

Access individual emails on Mac, Windows, Linux, or mobile

Select MSG File

Drag and drop any .msg file onto this window.

Local In-Memory Decode

Our parser unpacks MAPI descriptors and body streams directly in browser memory.

View & Export

Read the email, inspect headers, download attachments, and print to PDF.

MSG FAQs & Help

Frequently Asked Questions

Everything you need to know about viewing and exporting Outlook .msg files safely.

OmniPST MSG Viewer parses Microsoft Compound File Binary (CFB/OLE) formats directly in your web browser. You do not need Microsoft Outlook or an active Microsoft 365 subscription. Simply drag and drop your .msg file to view the email, headers, and attachments immediately.