How to open a .key file (Windows, Mac, Linux)

Q: Why can't I open my .key file?

Usually your computer lacks an app that understands Keynote. Install one of the apps listed here, or convert the file to a more common format.

A .key file is a Apple Keynote Presentation. If double-clicking does nothing, your computer simply does not have an app that reads Keynote yet. Here is how to fix that on each operating system, using free software wherever possible.

Open a .key file step by step

Confirm the file really is a .key. Drop it into the WhatFileType file identifier, which reads its signature without uploading anything.
On Windows, open it with iCloud Keynote (web) or convert to PPTX first.
On Mac, use Apple Keynote or Preview (quick look).
On Linux, try iCloud Keynote (web).
Still stuck? Convert the .key to pptx, which opens more widely.

Best apps to open .key files

Windows

iCloud Keynote (web)
convert to PPTX first

macOS

Apple Keynote
Preview (quick look)

Linux

iCloud Keynote (web)

Web

iCloud.com Keynote

Before you open it: Safe. A .key file is a presentation package, not a program.

Frequently asked questions

Why can't I open my .key file?

Almost always because no installed app understands Keynote. Install one of the apps above, or convert the file to a format your existing software already reads.

How do I open a .key file on Windows?

Use iCloud.com Keynote in a browser, or ask the sender to export it to PowerPoint (.pptx) or PDF from Keynote.

Can PowerPoint open a .key file?

Not directly. Export it from Keynote as .pptx first, then PowerPoint opens it, though complex animations may not survive.