How to Change the Default Mac App for a File Type

Any time a user installs a new application on a Mac, it becomes the default Mac app for that file type. For example, PDF files open by default in the Mac Preview app. However, if a user downloads and installs Adobe’s Acrobat Reader or Adobe Acrobat DC, the default file type will change so that all PDF files will open with Adobe Acrobat. We’ll show users how to take control of what apps open when they double-click a certain file type. Changing the Default Mac app is a simple procedure that will save users some time and avoid annoyances.

Why Change Default Mac App for a File Type

New MacBook pro Looks Like The Old MacBook Pro maybe

Why would you want to change a default Mac app for a file type? Let’s say you want to open a video file using VLC Media player instead of Apple’s QuickTime Player. Maybe you want all JPG picture files to open in a photo editor instead of OS X Preview.

These and other file types open in a default program set by the operating system. The installation procedure of some apps will change the default. They’re not supposed to change the default Mac app for a file type without the user’s agreement. However, you may not see the dialog box that asks for permission.  Likewise, the programmer may not ask for the permission in a way that makes it clear that the program’s changing your default app. Follow the steps below to fix this or change it.

How to Change Default Mac App for Any File Type

Find a file of the type you want to change the default mac app for by opening Finder. Some file types won’t show you the extension that identifies the type of file. The extension is the ending of the file. For example a picture file type known as JPEG has a file ending of JPG. So a file might carry the name photo0003.jpg. Notice the three letters after the period are JPG. Other common file types you may wish to change include …

  • PDF – portable document format also called Acrobat files, which open in Preview by default
  • GIF – another image format called Graphics Interchange Format which opens in Preview by default
  • DOC – a document file often associated with Word or some other word processor
  • DOCX – a proprietary Microsoft Word format
  • MP3 – music files, which open in iTunes by default
  • M4V – a video format
  • MP4 – another video format
  • MOV – movie files, which open in QuickTime by default

When a user opens Finder and looks at a file, they might not see these endings. To make sure you can see yours, open Finder and then, from the Finder menu at the top left select Preferences. You can also use the keyboard shortcut COMMAND + , (the comma).

open finder preferences in os x

Inside the ensuing dialog box open the Advanced tab by clicking Advanced in the top right corner of the box.

Show all filename extensions in Mac OS X

Click to put a check mark in Show all filename extensions in that dialog box. Exit the box by clicking the red button in the upper left corner. From now on you’ll see all the file extensions of every file in Finder.

Now search for a file with the extension you want to change. For example, you installed Acrobat and the installation procedure moved the default app from the OS X Preview app to Adobe Acrobat DC. You don’t want to open the Adobe Acrobat document creator program from Creative Cloud suite just to view a PDF file. Instead, you want to see all PDF files in Preview. Find a PDF file stored on your computer using Finder. If you can’t find one use the search box in Finder. It’s in the upper right corner (see below).

search in finder

Once you find a file, right-click on the file and choose Get Info from the menu that pops up.

choose get info from right-click menu

A dialog box will open. Look for the Open With section. You’ll see a drop down box.

change open with to change default mac app type

The drop down box will list all the OS X apps that can handle that file type. Choose the preferred program and it will instantly change the default Mac app for that file type.

The Change All button will change all file types for that app so that any other customizations will revert back to defaults. For example, all file types that normally open with Microsoft Word will change back to opening with Word. If you changed one of the types, like the DOC file format making it open in another word processor while keeping DOCX files assigned to Word, clicking Change All will change both back to Word. So pick it only when you know what you’re doing.

You may want to go back into Finder’s preferences to hide file extensions after you finish because all apps will start showing their .app file extension. If seeing the .app extension annoys you follow the steps above to hide the extensions in Finder Preferences.

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