What are COMPANION files and how to open them

Are you having problems opening a COMPANION file or just wondering what they contain? We explain what these files are used for and show you software that we know can open or otherwise handle your files.

What is a COMPANION file?

The COMPANION file extension indicates to your device which app can open the file. However, different programs may use the COMPANION file type for different types of data.

While we do not yet describe the COMPANION file format and its common uses, we do know which programs are known to open these files, as we receive dozens of suggestions from users like yourself every day about specific file types and which programs they use to open them.

We are continually working on adding more file type descriptions to the site, so if you have information about COMPANION files that you think will help others, please use the Update Info link below to submit it to us - we'd love to hear from you!

How to open COMPANION files

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

While we have not verified the app ourselves yet, our users have suggested a single COMPANION opener which you will find listed below.

Various apps that use files with this extension

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

OpenTX CompanionOpenTX CompanionUser submitted

Try a universal file viewer

Try a universal file viewer like Bitberry File Opener. It can open 410 different types of files - and most likely yours too. Download Bitberry File Opener here.

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