Change file associations on the Mac and set the default app

How do you open a file on an Apple Mac? The quick way is to double click it, which opens it in the default app. What if the default app isn’t the one you want? Change the file association.

Common files like documents, spreadsheets, photos, videos, audio, PDF and so on, all have an app associated with them. When a file is double clicked in Finder, macOS looks up the app associated with that file type and opens the app, which in turn, opens the file. It saves you having to find the app, run it, go to the File menu, and so on.

This works very well most of the time and it is quick and convenient to open files from Finder. For example, you can open a Finder window, which then shows your most recent files. Double clicking one opens it for editing.

The problem is that you may have several apps that can open a particular type of file. For example, a text file could open in TextEdit, Pages or Notes Apple apps, or in an app you have added, like Bean, BBEdit, Word or something else.

You may prefer to open text files in BBEdit instead of the default TextEdit, or you might want to open JPEG images in GIMP rather than Preview, and so on. You might even find that installing an app changes the default file association to it, when you would rather keep the default.

Let’s see how to change file associations on the Apple Mac and choose which app opens a particular file or type of file.

1 Show file extensions

Show file extensions in Finder preferences on the Apple Mac

Although it is possible to have files with no filename extension, files usually have one, like .jpg or .txt. If you do not see filename extensions in Finder windows, they may be hidden.

Go to the Finder menu and select Preferences. Select the Advanced tab and then tick Show all filename extensions. It is useful to see them and not only can the Mac tell what type a file is, you can too.

2 Choose an app with Open With

Ctrl+click a file in macOS to show a menu with Open With

Double clicking a file in a Finder window or on the desktop opens it in an app, but what if it is the wrong one? Ctrl+click the file and in the menu that is displayed, hover the mouse over Open With. It shows the default app and any alternative apps that are capable of opening the file. Select the app you want to open the file with using this menu.

3 Set the file’s default app

Always open a file with a specific app in macOS on the Apple Mac

If you always want to open this file with a specific app, Ctrl+click it and then hold down Alt/Option key and Open With changes to Always Open With. Select the app you always want to open this file with.

This sets the default app only for this file and no others. This is useful if you want to open a particular file in an app without changing any other files.

4 Associate a file with an app

Associate a file with an app in macOS on the Apple Mac

There is another way to set the file association to a particular app. Select a file in a Finder window or on the desktop and press Cmd+I to open the Info window. Look for the section called Open with and expand it if it is not expanded. Click the default app and a list of apps capable of opening this file is displayed. Select a different app from the list to make it the default.

This affects only this file and no others.

5 Associate all files with an app

Set all files of a certain type to open with an app in macOS on the Apple Mac

After selecting an app to open this file, click the Change All button just below if you want to change the association for all files of this type. This sets a new system-wide default association and all files will open in the selected app.

If you have installed software which has changed the default file association and files now open in the wrong app. Find just one file, press Cmd+I and set the Open with association back to what it was before using the Info window.

It can be confusing at first, because it is possible to change associations for one file or all files. Be clear about what you are changing.