What Is a KEY File? (2024)

What to Know

A KEY file could be a software license or Keynote Presentation file.
Not all of them open the same way, but trying a text editor is a good start.
Some can be converted to PPT with Keynote.

This article explains all the different formats that use the KEY file extension and how to open and convert each one, if possible.

Definition of a KEY File

A file with the .KEY file extension might be a plain text or encrypted generic license key file used to register a software program. Different applications use different KEY files to register their respective software and prove that the user is the legal purchaser.

A similar file format uses the KEY file extension as a way to store general registration information. It's most likely created by the program when a product key is used and might be transferable to other computers should the user need to reinstall the software elsewhere.

Another kind of KEY file is a Keynote Presentation file created by the Apple Keynote software. This is a kind of presentation that might include slides that contain images, shapes, tables, text, notes, media files, XML-related data, etc. When saved to iCloud, ".KEY-TEF" is used instead.

Keyboard Definition files are saved with the .KEY file extension as well. They store information regarding computer keyboards, like shortcut keys or layouts.

Unrelated to a KEY file is a registry key in the Windows Registry. Some license or registration files might instead just be called a keyfile and not use a specific file extension. Others might be in the PEM format that store public/private encryption keys.

How to Open a KEY File

It's important to know which file format your KEY file is in before deciding how to open it. Even though all of the programs mentioned below can open KEY files, it doesn't mean that they can open KEY files that belong to other programs.

License or Registration Files

If your antivirus program happens to use a KEY file to register the software and prove that you're the one who purchased it, then you need to use that program to open your KEY file.

LightWave is one example of a program that uses a KEY file to register it as a legal copy.

If it is, in fact, a license key file you have, you might also be able to read the license information with a text editor like Notepad.

It's important to reiterate that not every KEY file can be opened with the same program, and this is also true within the context of software license keys. For example, if your file backup program requires a software license file, you can't expect to use it to register your antivirus program (or even any other backup program that isn't the one that the KEY file belongs to).

Registration files are probably encrypted and can't be viewed, and they probably don't even need to be. They might be copied elsewhere should the scenario arise that the program using it is installed elsewhere and the old one deactivated.

Since they're specific to each program that uses them, contact the software developer if you can't get yours to work as it should. They'll have more information regarding how it's supposed to be used.

Keynote Presentation KEY Files

You can open KEY files on macOS using Keynote or Preview. iOS users can use KEY files with the Keynote app.

Keyboard Definition KEY Files

Opening keyboard-related KEY files is only useful in a program that supports custom keyboard shortcuts. If you don't have such an application, you might be able to read its instructions with a text editor.

How to Convert KEY Files

Of the file formats mentioned above that use the KEY file extension, it only makes sense to convert a Keynote Presentation file, which you can with the Keynote program for macOS.

With it, KEY files can be exported to PDF, MS PowerPoint formats like PPT or PPTX, HTML, M4V, and image file formats like PNG, JPG, and TIFF.

The iOS version of the Keynote app can export the file to PPTX and PDF.

Another method is to use an online KEY file converter like Zamzar to save the file to KEY09, MOV, or one of the formats mentioned above, like PDF or PPTX.

Another desktop alternative is Filestar, which supports converting a KEY file to over a dozen formats.

Still Can't Open the File?

If your file won't open with the software from above, double-check that the extension reads ".KEY" and not something that just looks similar. It's easy to confuse one for a KEYCHAIN, KEYSTORE, or KEYTAB file.

If you don't really have a KEY file, it's best to research the actual file extension for details on what opens or converts that specific file type.

FAQ

What is a file encryption key (FEK)?

The FEK is a symmetric key used to encrypt the data in a file protected by the Windows Encrypting File System (EFS). Windows further encrypts the FEK and stores it in the file metadata so only authorized users can access it.
What happens when the encryption key is lost on a file in Windows?

You can reverse the encryption to access your file. Right-click the file, go to Properties > General > Advanced, and clear the Encrypt contents to secure the data check box. Click OK twice to apply the changes and exit the window.

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