The Ultimate Guide: How to Play Any Video File (MKV, AVI, WebM) on a Mac

Nov 15, 2025 · 3 min read · You double-click a video file someone sent you. It's an .mkv, an .avi, or a .webm. Instead of your video playing, you get the same frustrating error: "The file ... is not compatible with QuickTime Player." We've all been there. We love our Macs for t...