.PUB file extension

To open .PUB files on Windows, install and open Microsoft Publisher, then use File > Open to open the .PUB file.

To open a .PUB file, use Microsoft Publisher on Windows. On macOS, Linux, iOS, and Android there is typically no full-fidelity native support, so you’ll usually need to open it on a Windows PC with Publisher (or try an importer that may not preserve layout perfectly).

Home Extension Index Documents in index Documents category page

Last updated: June 11, 2026 · Reviewed by Julian Stricker

What “reviewed” means on this page

Format fit: whether the “what is this file?” description matches common real-world use of the extension, including category, typical MIME types, and aliases.
Opening paths: whether Windows / macOS / Linux steps read plausibly for current OS dialogs and default apps; we remove fantasy menus and unsafe shortcuts.
Security framing: whether risk notes match the extension class (for example executables vs plain data) and whether affiliate wording does not contradict the security section.
Sources and further reading: whether external links point to vendors, standards bodies, or other primary references where possible; we avoid inventing details we cannot ground.
Limits: this is clarity and safety-messaging QA, not a guarantee that every statement is exhaustive or that every binary you download is harmless.

Full methodology in the Imprint — The Imprint also states where AI is used and what that does—and does not—replace.

Open on your device

Choose your operating system for a dedicated step-by-step opening guide.

How to open .PUB files

Use these platform-specific instructions to open .PUB files safely.

Windows

Install and open Microsoft Publisher, then use File > Open to open the .PUB file.
If you don’t have Publisher, try opening/importing the .PUB file in an app that supports Publisher import (results may vary).

Full Windows guide

Mac

If you need accurate layout, transfer the file to a Windows PC and open it in Microsoft Publisher.
Otherwise, try an application that can import Microsoft Publisher files, understanding that formatting may change.

Full Mac guide

Linux

Try opening/importing the .PUB file in an application that supports Microsoft Publisher import (formatting may be incomplete).
If fidelity matters, open the file on Windows using Microsoft Publisher.

Full Linux guide

iOS

iOS typically won’t open .PUB with full fidelity; share or transfer the file to a Windows PC and open it with Microsoft Publisher.

Full iOS guide

Android

Android typically won’t open .PUB with full fidelity; transfer the file to a Windows PC and open it with Microsoft Publisher.

Full Android guide

Security notes

.PUB is a complex, proprietary format; treat files from unknown sources as potentially risky because document parsers can have vulnerabilities.
Prefer opening untrusted .PUB files in a trusted, fully updated viewer/editor (ideally Microsoft Publisher) rather than relying on unknown importers.
Be cautious with .PUB files received unexpectedly (especially if they prompt you to install software or enable special features); verify the sender and context first.

If you did not expect this file

This extension is usually plain data, text, or structured content—not a program by itself. The practical risk is social engineering (a scam attachment or misleading filename). For trusted senders you rarely need heavy-handed antivirus wording; use these tools when you want an extra check on unexpected downloads.

Avast

Avast offers free and premium antivirus software that protects against viruses, malware, ransomware, and phishing. Scan files before opening them to ensure safety.

Norton

Norton 360 delivers comprehensive antivirus protection, VPN, and identity theft monitoring. Scan files for threats before opening to keep your device secure.

We may earn a commission when you use affiliate links. This supports our free file extension guides.

Can't open this file?

These are the most common causes and fixes when .PUB files fail to open.

Common reasons

The .PUB file won’t open or shows as an unknown format
Layout/formatting changes after opening in another app
A tool identifies the file as application/x-mspublisher but your workflow expects another MIME type

Fix steps

On Windows, install Microsoft Publisher and open the file from within Publisher (File > Open).
On non-Windows devices, move the file to a Windows PC with Publisher for the most reliable results.

OS-specific troubleshooting

Convert .PUB to other formats

Use conversion tools to change .PUB files into formats your software supports.

.PUB → .PDF

What is a .PUB file?

.PUB is a proprietary publication/document format used by Microsoft Publisher. It is designed for page-layout content (brochures, flyers, newsletters) and may not round-trip cleanly through non-Microsoft tools. In content detection systems, it is commonly identified as application/x-mspublisher.

Background

Microsoft Publisher uses .PUB as its native file format for desktop publishing and page layout. Files often include complex layout elements (positioned text boxes, images, shapes, and fonts) meant to print or export as a final document.

Because the format is proprietary, third-party applications may be able to import .PUB files, but results can vary depending on the Publisher version and the document’s complexity. In practice, the most reliable way to preserve the original layout is to open the file in Microsoft Publisher.

In enterprise and indexing tools, Microsoft Publisher files are recognized as their own document type; for example, Microsoft documentation and Apache Tika identify them with the MIME type application/x-mspublisher. For general web/standards use, you should not assume there is an official IANA-registered media type specifically for Microsoft Publisher.

Common MIME types: application/vnd.exstream-package

Common .PUB issues

The .PUB file won’t open or shows as an unknown format

This usually happens when Microsoft Publisher (or a compatible importer) isn’t installed on the device, or the OS has no associated app for .PUB.

On Windows, install Microsoft Publisher and open the file from within Publisher (File > Open).
On non-Windows devices, move the file to a Windows PC with Publisher for the most reliable results.

Layout/formatting changes after opening in another app

Because .PUB is proprietary, importers may not fully support all layout features, fonts, or embedded objects.

Open the file in Microsoft Publisher to preserve layout and typography as authored.
If you must use an importer, compare the output carefully (especially text reflow, image placement, and missing fonts).

A tool identifies the file as application/x-mspublisher but your workflow expects another MIME type

Some systems detect .PUB as application/x-mspublisher; assuming an IANA-registered type may cause handling issues in strict pipelines.

If you control the pipeline, allow application/x-mspublisher for Publisher content where appropriate.
If you need broader compatibility, open in Publisher and export to a more widely supported format used by your workflow.

FAQ

What program opens .PUB files?

Microsoft Publisher is the primary program for .PUB files. Other applications may import .PUB files, but results can vary and the original layout may not be preserved.

Is there an official MIME type for Microsoft Publisher (.pub)?

In practice, Microsoft documentation and tools like Apache Tika commonly use application/x-mspublisher for .PUB. You should not assume there is an IANA-registered media type specifically for Microsoft Publisher.

Can I open a .PUB file on Mac, iPhone, or Android?

There is typically no full-fidelity native support on those platforms. The most reliable approach is to open it on Windows with Microsoft Publisher, or use a third-party importer with the expectation that formatting may change.

Can I convert a file by renaming it to .PUB?

No. Renaming only changes the extension label. Use the original app’s export/save-as features or a proper conversion workflow.

Similar file extensions

Compare related formats in the same category to find the right tool faster.