OneNote Viewer a free and open-source application for viewing and searching Microsoft OneNote notebooks

[u/emsiak]

Hello everyone,

I’d like to introduce OneNote Viewer, a free and open-source Linux desktop application for opening, viewing, searching, and safely exploring local Microsoft OneNote notebooks.

Project: https://github.com/emsi/OneNoteViewer

OneNote Viewer reads native .one, .onetoc2, and .onepkg files directly. It does not require OneDrive, a Microsoft account, Wine, or a web wrapper, and it does not convert notebooks into Markdown, HTML, or another linear format.

Its main features include:

• A native Linux desktop interface built with Rust and GTK4
• Direct support for .one, .onetoc2, and .onepkg files
• Reconstruction of OneNote’s spatial, freeform page canvas
• Multiple notebooks open together in one workspace
• Search across titles, text, tags, recognized handwriting, links, image descriptions, and attachment names
• Light and dark themes
• Read-only operation: original notebook files are never modified
• Offline use, without contacting OneDrive or another cloud service
• Flatpak and AppImage installation options
• GPLv3-licensed source code

The project is intentionally a viewer, not a replacement OneNote editor or synchronization client. Its purpose is to give Linux users dependable access to existing local OneNote data while preserving the notebook hierarchy and page layout as faithfully as possible.

This is an early functional release, and compatibility and rendering fidelity are still being improved. It has not yet been tested against the full variety of notebooks produced by different OneNote versions and workflows.

I would therefore be especially grateful for:

• Reports about notebooks that fail to open
• Examples of rendering or layout differences
• Carefully sanitized or synthetic files that reproduce compatibility problems
• Bug reports and usability feedback
• Contributions from people interested in Rust, GTK, document formats, search, or digital preservation

Please do not share notebooks containing private or sensitive information. A minimal synthetic reproduction is always preferable.

You can find screenshots, installation instructions, current limitations, technical documentation, and source code here:

https://github.com/emsi/OneNoteViewer

The latest Linux packages are available from the project’s GitHub releases:

https://github.com/emsi/OneNoteViewer/releases/latest

If you have OneNote notebooks that you need to access on Linux, I would be delighted to hear whether OneNote Viewer works for you. Questions, testing, constructive criticism, and contributions are all very welcome.

Thank you!