Encountering issues playing AVI files on your Mac? Learn how to seamlessly convert them to MP4 using two popular programs: HandBrake and Free MP4 Converter.
Steps to Convert AVI to MP4
Using Free MP4 Converter

Access the App Store.

Enter 'Free MP4 Converter' in the search bar.

Tap 'GET' below Free MP4 Converter.

Tap 'Install App'.

Tap 'Add File'.

Choose an AVI file.

Tap 'Open'.

Choose MPEG-4 Video.

Tap 'Convert'.
Launch Handbrake.

To get HandBrake for Mac, download and install it here. If prompted, allow apps downloaded from unidentified sources in System Preferences > Security and Privacy.

Tap 'Open Source'.

Choose an AVI movie and tap 'Open'.

Pick 'MP4 File' under 'Format:'.

Press 'Start'.