Software & Apps File Types What Is a KEY File? How to open, edit, and convert KEY files By Tim Fisher General Manager, VP, Lifewire.com Tim Fisher has 30+ years' professional technology support experience. He writes troubleshooting content and is the General Manager of Lifewire. our editorial process Facebook Twitter LinkedIn Tim Fisher Updated November 25, 2019 File Types Design Cryptocurrency MS Office Windows Linux Google Drive Apps File Types Backup & Utilities View More Tweet Share Email 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 type of presentation file 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 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. Still 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 KEY Files For example, 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 KEY 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). KEY files that are registration files are probably encrypted and can not be viewed, and they probably don't ever 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 a program that can use the KEY file, 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 KEY files 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. Still Can't Open the File? If your files don't open with the software from above, double-check that the file extension reads ".KEY" and not something that just looks similar. It's easy to confuse KEY files and KEYCHAIN, KEYSTORE, and KEYTAB files. 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.