Normally, .key files are only opened using Keynote. However, Powerpoint, Windows’ own presentation software application, can open these types of files, too.

How to open a .key file on windows

  1. Open PowerPoint.
  2. From the navigation bar on the side of PowerPoint, click Open. This should show you a list of your PowerPoint files and other options.
  3. Under “Other locations,” click Browse. This action will open a navigation window. 
  4. On the file types dropdown, change “All PowerPoint Presentations” to “All Files.”
  5. Navigate to the location of your .key file, and select your file.
  6. Lastly, click the Open button at the bottom-right corner of the navigation window.