When opening files on your Mac, there is always a default application set to open it. Many times, proprietary files can only open in one program, i.e. an Excel (.xls) file will only open in Microsoft Office Excel. Other files, such as a PDF or MP3, can be opened by several different applications. There may be a specific application you prefer using or an application you particularly don’t want to use. The default opening application can be changed in the info window of any file type.
Find a file that you want to specify its default application. A PDF file is one of the more versatile file types that can be opened by several applications, so we will be working with a PDF.
CTRL-Click or Right Click the file to bring up its contextual menu. Roll your mouse over the Open With option. This will show you all the applications that can open this specific file type.
Move the mouse down and click on Get Info.
The info window will appear with several sections, including Name & Extension, Preview, Permissions, etc.
Expand the Open with section to choose the default application.
Click on the Drop-Down Menu to reveal your choices of applications. Click an Application to set it as the default.
This file is now set to open with the application of your choosing. If you want all files of this type to be opened by that application, click on the Change All button below the drop-down menu.
