What Is an EFX File?

This article describes two files formats that use the EFX file extension, including how to open and convert both kinds.

What Is an EFX File?

A file with the EFX file extension could be an eFax Fax document. They're used by the eFax service, which lets you send and receive faxes over the internet.

Another use for this file extension is as an effects file for the Star Wars Jedi Knight: Jedi Academy video game.

How to Open an EFX File

EFX fax files are used with the eFax Messenger application. While that program is completely free to download and install, it won't actually work unless you log in with a Plus, Pro, or Corporate eFax account.

eFax Messenger is also used to make an EFX file; you can open TIF, HOT, JPG, GIF, BMP, AU, JFX, and other files directly in the program to save to the EFX format or to immediately send it as a new fax.

Once you've opened the EFX file, or any supported format for that matter, use the File > Create New Fax menu to send the fax.

Other EFX files are used by the Star Wars Jedi Knight: Jedi Academy game, but it's unlikely that you can actually open them manually within the game. Chances are that the file is used by the game on an as-needed basis and is stored somewhere in its installation folder, but isn't meant to be used by you.

How to Convert an EFX File

eFax Messenger can convert an EFX file to PDF, TIF, and JPG. You do this through the program's File > Export menu item. Use File > Save As if you want to convert other documents to the EFX format or save your fax as a black and white TIF image.

If you need the file to be in some other format not supported by eFax Messenger, first convert it to a supported format (like JPG) and then convert that file to something else using a free file converter. You can't see the Export option in the menu until you switch eFax Messenger to Fax Edit mode, which you can do from the right-hand side of the program.

It's highly unlikely that a Star Wars effects file can be converted to any other format. In fact, doing so would probably render it unusable in the game.

Still Can't Open the File?

If your file won't open after trying the suggestions explained above, it's more than likely the case that you're misreading the file extension. Other file extensions might look a lot like they read "EFX," but if they don't, then they'll need to be opened with a different program.

For example, EFX files aren't the same as FXB or FDX files even though their file extensions look similar. Follow those links to learn more about how to use those files.

Another is EFW. Although the first two letters are the same as EFX, that's really just a renamed ZIP or executable file, and therefore opens with a different program.