.TM file extension

To open .TM files on Windows, install GNU TeXmacs from the official TeXmacs website.

To open a .TM file, use GNU TeXmacs (the editor that creates TeXmacs documents). If you don’t have TeXmacs installed, ask the sender to export the document to a more common format (PDF/HTML/XML) from TeXmacs.

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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 .TM files

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

Windows

Install GNU TeXmacs from the official TeXmacs website.
In TeXmacs, use File → Open and select the .tm file (or right-click the file → Open with → GNU TeXmacs).
If you only need to read it, ask the author to export from TeXmacs to PDF/HTML for easy viewing.

Full Windows guide

Mac

Install GNU TeXmacs from the official TeXmacs website.
Open TeXmacs and choose File → Open, then select the .tm file.
If it won’t open, confirm the file is actually a TeXmacs document (not an unrelated “.tm” file from another tool).

Full Mac guide

Linux

Install GNU TeXmacs (from your distribution packages or from the official TeXmacs website, depending on your system).
Open TeXmacs and use File → Open to load the .tm file (or open it from your file manager with GNU TeXmacs).
If file associations are missing, you may need to set GNU TeXmacs as the default app for .tm files in your desktop settings.

Full Linux guide

iOS

iOS typically cannot open TeXmacs .tm documents directly; transfer the file to a desktop system with GNU TeXmacs or ask the sender to export to PDF/HTML.

Full iOS guide

Android

Android typically cannot open TeXmacs .tm documents directly; transfer the file to a desktop system with GNU TeXmacs or ask the sender to export to PDF/HTML.

Full Android guide

Security notes

Treat .tm files as untrusted input when received from unknown sources: like any complex document format, opening it requires parsing, and vulnerabilities in document parsers can exist.
Prefer opening unknown .tm files in an up-to-date GNU TeXmacs installation, and avoid enabling or running any embedded Scheme-related features unless you trust the document source (TeXmacs supports Scheme as part of its ecosystem).
If you only need to read the content, request an exported PDF/HTML from the sender to reduce reliance on specialized parsing and features.

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.

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Can't open this file?

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

Common reasons

The .TM file opens in the wrong program (or not at all)
You’re on iOS/Android and can’t preview the file
Text looks unreadable when opened in a plain text editor
File appears corrupted or incomplete

Fix steps

Install GNU TeXmacs and open the file from inside TeXmacs (File → Open).
Change the default app for .tm files to GNU TeXmacs (Windows/macOS/Linux file association settings).
If TeXmacs cannot parse it, confirm with the sender what program created the file (since “.tm” can be used by unrelated software).

OS-specific troubleshooting

What is a .TM file?

A .TM file is a TeXmacs document serialized in the TeXmacs syntax (TeXmacs’ native storage format), as documented by the TeXmacs project. It is primarily meant to be opened and edited inside GNU TeXmacs, and TeXmacs can also export documents to other formats such as XML.

Background

GNU TeXmacs is a scientific text editor and typesetting system that stores documents in its own native format, typically using the .tm extension. TeXmacs documents are not plain text in a standard office format; they are stored using TeXmacs’ own document syntax and are intended to round-trip accurately when opened again in TeXmacs.

In practice, .tm files are used in academic and technical workflows (mathematics, physics, computer science notes) where users want a structured editor with strong support for formulas and document structure. The official documentation describes how TeXmacs serializes documents and related formats, and TeXmacs can save or export to other representations (for example, XML-based variants) depending on the workflow.

Because “.tm” is a short extension, other unrelated uses may exist in the wild. When users refer to “TM Document File” in a document context, the most common and well-documented meaning is a GNU TeXmacs document.

Common MIME types: text/texmacs

Common .TM issues

The .TM file opens in the wrong program (or not at all)

This usually happens because the system has no TeXmacs association for .tm, or the file is not a TeXmacs document.

Install GNU TeXmacs and open the file from inside TeXmacs (File → Open).
Change the default app for .tm files to GNU TeXmacs (Windows/macOS/Linux file association settings).
If TeXmacs cannot parse it, confirm with the sender what program created the file (since “.tm” can be used by unrelated software).

You’re on iOS/Android and can’t preview the file

Mobile operating systems generally do not include viewers for TeXmacs’ native .tm format.

Open the file on a desktop (Windows/macOS/Linux) with GNU TeXmacs.
Ask the author to export the document from TeXmacs to PDF/HTML for mobile viewing.
If you must share it with others, prefer exporting to a common format rather than renaming the extension.

Text looks unreadable when opened in a plain text editor

.tm is TeXmacs’ structured document format and is not intended to be edited with generic text editors.

Open the file in GNU TeXmacs for correct rendering and editing.
Use TeXmacs’ export options if you need a plain-text or exchange-friendly format (for example, an XML-based export).

File appears corrupted or incomplete

Interrupted downloads/transfers or mismatched encodings can cause TeXmacs to fail when loading a document.

Re-download or re-copy the file and try opening it again in GNU TeXmacs.
Ask the sender to re-export or re-save the document from TeXmacs and resend it.
If available, try opening a known-good .tm file to verify your TeXmacs installation is working.

FAQ

What program opens a .TM document file?

The most common “.TM document” is a GNU TeXmacs document; open it with GNU TeXmacs.

Is .tm the same as TeX or LaTeX?

No. TeXmacs is a separate editor and its native .tm format is not the same as a .tex (LaTeX/TeX) source file, even though they can be used in related scientific writing workflows.

Can I convert a .tm file by renaming it to .pdf or .docx?

No. Use GNU TeXmacs to export to another format (for example PDF/HTML/XML), or ask the author to export it for you.

Is the MIME type text/texmacs officially registered?

Verify MIME type registration using the IANA media types registry; if it is not listed there, it is not an officially registered IANA type.

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