on the Mac, here's how to change the default application used to open a given file type. Open a finder window and find a file of the type you want to change. Once you found the file in the finder, click on the "More info..." button. There are a bunch of sections in the window that opens with more information. The one you care about is the "Open with:" section.



In this section you can select the application you want to open this file from the pull down menu. If you want to change this for all files of this type, once you choose the application you want hit the "Change All..." button. You'll have to confirm this change. Once you do, the selected application will always be used to open files of the given type.