BTR File

What are BTR files and how to open them

Are you having problems opening a BTR file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your BTR files.

What is a BTR file?

A .BTR file is a FrontPage Binary-tree Index file.

FrontPage Binary-tree index files are used by Microsoft FrontPage's Server Extensions to store internal metadata about a web site - particularly dependencies among pages, hyperlinks, and document relationships. They support FrontPage's ability to update links, propagate changes, and maintain navigation without re-scanning every page all the time.

These files are created and maintained automatically by the FrontPage Server Extensions. Changes to a web site - editing, adding, removing pages - cause recomputation of certain links and dependency information, which gets stored in these binary-tree index files. They are not image or document content; they are support files used behind the scenes to speed up hyperlink and document dependency operations.

The format begins with a specific binary header: at offset 0 is the byte sequence 1C 01 00 00, and at offset 6 the sequence 00 00 0C 01 00 00 35 12 (ASCII showing "......5" in part) which help identify the format uniquely.

How to open BTR files

Important: Different programs may use files with the BTR file extension for different purposes, so unless you are sure which format your BTR file is, you may need to try a few different programs.

While we have not verified the apps ourselves yet, our users have suggested two different BTR openers which you will find listed below.

Last updated: August 25, 2026

Various apps that use files with this extension

These apps are known to open certain types of BTR files. Remember, different programs may use BTR files for different purposes, so you may need to try out a few of them to be able to open your specific file.

Help us help others

File.org helps thousands of users every day, and we would love to hear from you if you have additional information about BTR file formats, example files, or compatible programs. Please use the links below or email us at submit@file.org to discuss further.