How to change the default application for file extensions on Mac

In some cases it is necessary to change which application is used for a specific file extension. If you found a found a better movie player, text editor, or image viewer you may want to use that application for all files with the same file extension.

For example, QuickTime Player is the default application for viewing MP4 movie files on OS X, but VLC could be your media player of choice.

Follow these steps to change your default preferences:

  1. Find a file with an extension you want to change the defaults to.
  2. Right click on the file to see a menu, and select “Get Info”.
    (right click is a two finder click on a trackpad)
  3. A window appears with the file’s information, see the section called “Open with”
  4. It will display the current application used for this file, use the dropdown box to select you new application. If you do not see your new application in the dropdown box, use the “Other” selection to browse for it.
  5. Click on the “Change All” button to apply the change to all files ending with the same file extension. That’s all.

Further notes:

You can always override the default by manually opening the file in a different application with a simple right click, and “Open With” command when the default is not appropriate.

To make it easier to distinguish between file extensions you may want to also enable the option to make all file extensions visible. In Finder, select Preferences in the top menu, and click on the Advanced tab. Check the box that’s labeled “Show all file name extensions”.